Acquisitions and Dispositions - Purchase Price Allocation (Details) $ in Millions	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jul. 29, 2019 USD ($) entity	Dec. 31, 2018 USD ($)
Assets acquired
Goodwill	$ 36,322	$ 36,038		$ 5,702
Net assets acquired
Number of entities to dispose | entity			2
First Data
Assets acquired
Cash and cash equivalents			$ 310
Trade accounts receivable			1,747
Prepaid expenses and other current assets			1,047
Settlement assets			10,398
Property and equipment			1,156
Finite-lived intangibles assets			16,272
Goodwill			30,811
Investments in unconsolidated affiliates			2,676
Other long-term assets			1,191
Total assets acquired			65,608
Liabilities assumed
Accounts payable and accrued expenses			1,613
Short-term and current maturities of long-term debt			243
Contract liabilities			71
Settlement obligations			10,398
Deferred income taxes			3,671
Long-term contract liabilities			16
Long-term debt and other long-term liabilities			1,261
Total liabilities assumed			17,273
Net assets acquired
Net assets acquired			48,335
Redeemable noncontrolling interests			252
Noncontrolling interests			1,608
Total purchase price			46,475
Elan Financial Services
Assets acquired
Trade accounts receivable		20
Prepaid expenses and other current assets		98
Property and equipment		9
Finite-lived intangibles assets		373
Goodwill		214
Liabilities assumed
Accounts payable and other current liabilities		(55)
Net assets acquired
Net assets acquired		659
Customer relationships | First Data
Assets acquired
Finite-lived intangibles assets			13,458
Customer relationships | Elan Financial Services
Assets acquired
Finite-lived intangibles assets		$ 370
Other intangible assets | First Data
Assets acquired
Finite-lived intangibles assets			$ 2,814