Not included in the count are an untold number of small donors whose names are not identified in campaign finance reports but together have given millions to the Clintons over the years.
The majority of the money - US$2 billion - has gone to the Clinton Foundation, one of the world's fastest-growing charities, which supports health, education and economic development initiatives around the globe. A handful of elite givers have contributed more than US$25 million to the foundation, including Canadian mining magnate Frank Giustra, who is among the wealthy foreign donors who have given tens of millions.
Separately, donors have given US$1 billion to support the Clintons' political races and legal defence fund, making capped contributions to their campaigns and writing six-figure cheques to the Democratic National Committee and allied super PACs.
The Post investigation found that many top Clinton patrons supported them in multiple ways, helping finance their political causes, their legal needs, their philanthropy and their personal bank accounts. In some cases, companies connected to their donors hired the Clintons as paid speakers, helping them collect more than US$150 million on the lecture circuit in the past 15 years.
The couple's biggest individual political benefactors are Univision chairman Haim Saban and his wife, Cheryl, who have made 39 contributions totalling US$2.4 million to support the Clintons' races since 1992. The Sabans have also donated at least $10 million to the foundation.
The Clintons kept big contributors in their orbit for decades by methodically wooing competing interest groups - toggling between their liberal base and powerful constituencies, according to donors, friends and aides who have known the couple since their Arkansas days.
They made historic inroads on Wall Street, pulling in at least US$69 million in political contributions from the employees and political action committees of banks, insurance companies, and securities and investment firms.
The Clintons' ties to the financial sector strained their bonds with the left, particularly organised labour. But unions repeatedly shook off their disappointment, giving at least US$21 million to support their races.
The Clintons' fundraising operation - US$3 billion amassed by one couple, working in tandem for more than four decades - has no equal.
By comparison, three generations of the Bush family, America's other contemporaneous political dynasty, have raised about $2.4 billion for their state and federal campaigns and half a dozen charitable foundations, according to a Post tally of their fundraising from 1988 through 2015 - even though the family has collectively held the presidency longer than the Clintons.
Both Clintons declined to be interviewed or comment for this article.
Josh Schwerin, a spokesman for Hillary Clinton, said campaign officials could not recreate the Post's work to verify its findings.
"However, it should be noted that it would be misleading, at best, to conflate donations to a philanthropy with political giving," Schwerin said. "And regarding the campaign contributions, the breadth and depth of their support is a testament to the fact that they have both dedicated their lives to public service and fighting to make this country stronger."
The Clinton donor network is now serving as both a prime asset and liability for the former first lady, US senator and Secretary of State as she seeks the Democratic presidential nomination.
Her imposing resources helped scare off would-be Democratic rivals, such as Vice President Joe Biden, and have positioned her well against her main challenger for the party nomination, Senator Bernie Sanders of Vermont. By the end of September, Clinton had raised US$35 million more than Sanders, and she had pulled in more than double the total collected so far by the top campaign fundraiser in the GOP field, retired neurosurgeon Ben Carson.
But in an election shaped by a mounting distaste for the influence of big money, Clinton's long-standing ties to a cadre of wealthy patrons cuts against her efforts to cast herself as a champion of the middle class and a leader who will challenge the influence of large donors.
The Clintons have also been quick to seize on new sources of funds: Cuban Americans in Florida, Chinese immigrant communities in New York and wealthy figures around the world. And they have embraced bold new forms of fundraising, finding ways to inject corporate donations into political causes through nonprofit organisations in Arkansas and unregulated national party accounts.
Most of all, the Clintons have excelled at leveraging access to their power and celebrity.
Following the advice of a young Democratic party finance chair named Terry McAuliffe, who is now Governor of Virginia, the Clintons used the White House to entertain major donors. Perks included overnights in the Lincoln Bedroom. After leaving office, Bill Clinton headlined high-wattage gatherings for foundation donors around the globe. And supporters this year are jockeying to host intimate receptions at their homes during which they get a chance to mingle with Hillary Clinton.
Building such a financial network - and nurturing it over four decades - is not easy, even with the perks of office.
Bill Clinton used his charisma and intellect to captivate new supporters. And Hillary applied her characteristic attentiveness - sending handwritten notes to celebrate engagements and new babies, and poetry books to comfort those in mourning - to win lifelong allies.
"She remembers everything we ever talked about," said close friend Susie Tompkins Buell, co-founder of Esprit, who, with her husband, Mark, has given US$420,000 to the Clintons' campaigns and US$11.25 million to their foundation.
"Hillary does not like to ask for money," Buell added. "It's not natural for her. But she's got really good people who work for her who speak for her, and she's very, very appreciative when she knows someone has done something for her. And you know it's sincere."
As she makes her second White House bid, Hillary Clinton is raising money in a dramatically different environment than her past campaigns. Since then, the Supreme Court has made it easier for wealthy individuals, corporations and unions to spend huge, unregulated sums on political activity.
She appears willing to embrace the new fundraising techniques.
If she secures the Democratic nomination, she is expected to bring in US$1 billion during this election cycle - possibly matching what she and her husband collected for all their previous campaigns combined.
