Acquisitions and Dispositions - Narrative (Details) - USD ($) $ in Millions						2 Months Ended	3 Months Ended			9 Months Ended
	Jun. 30, 2021	May 04, 2021	Feb. 02, 2021	Jan. 22, 2021	Feb. 18, 2020	May 11, 2021	Sep. 30, 2021	Jun. 14, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Jun. 30, 2020
Business Acquisition [Line Items]
Goodwill							$ 36,303			$ 36,303		$ 36,322
Noncontrolling interest decrease									$ 762		$ 762
Tax expense											112
Net pre-tax gain							22		19	80	3
Tax expense							54		124	300	176
Noncontrolling Interests
Business Acquisition [Line Items]
Noncontrolling interest decrease									726		726
Additional Paid-In Capital
Business Acquisition [Line Items]
Noncontrolling interest decrease									36		36
Banc of America Merchant Services | Corporate joint venture
Business Acquisition [Line Items]
Percentage of interest in joint venture													51.00%
Banc of America Merchant Services Joint Venture | Bank Of America
Business Acquisition [Line Items]
Pre-tax gain									36
Tax expense									13
Revaluation/Remeasurement gain									700
Additional consideration due from the Company									$ 24
Processing and other support services agreement, term (in years)									5 years
Banc of America Merchant Services Joint Venture | Bank Of America | Noncontrolling Interests
Business Acquisition [Line Items]
Noncontrolling interest decrease									$ 726
Banc of America Merchant Services Joint Venture | Bank Of America | Additional Paid-In Capital
Business Acquisition [Line Items]
Noncontrolling interest decrease									$ 36
Investment Services Business
Business Acquisition [Line Items]
Controlling interest sold (as a percent)					60.00%
Percentage of interest owned in affiliate					40.00%
InvestCloud
Business Acquisition [Line Items]
Capital contribution			$ 200
Net pre-tax gain										28
Tax expense										6
Disposal Group, Disposed of by Sale
Business Acquisition [Line Items]
Revaluation/Remeasurement gain											176
Consideration from sale of business					$ 578
Tax expense											112
Disposal Group, Disposed of by Sale | Investment Services Business
Business Acquisition [Line Items]
Controlling interest sold (as a percent)					60.00%
Pre-tax gain on sale											$ 428
Disposal Group, Disposed of by Sale | InvestCloud
Business Acquisition [Line Items]
Tax expense										8
Proceeds from sale of entire ownership interest	$ 466
Pre-tax gain on sale										33
Pineapple Payments
Business Acquisition [Line Items]
Payments for acquisitions of businesses		$ 207
Acquired cash		6
Earn-out provisions estimated fair value		30
Measurement period adjustments, decrease in goodwill							42
Measurement period adjustments, increase in intangible assets							46
Measurement period adjustments, decrease in other net assets							$ 4
Intangible assets		127
Goodwill		82
Other net assets		4
Goodwill, expected tax deductible amount		59
Pineapple Payments | Acquired software and technology
Business Acquisition [Line Items]
Intangible assets		6
Pineapple Payments | Customer relationships
Business Acquisition [Line Items]
Intangible assets		$ 90
Ondot
Business Acquisition [Line Items]
Payments for acquisitions of businesses				$ 271
Acquired cash				13
Measurement period adjustments, decrease in goodwill										37
Intangible assets				142
Goodwill				173
Pre-tax gain from remeasurement										12
Measurement period adjustments, deferred income taxes										8
Ondot | Acquired software and technology
Business Acquisition [Line Items]
Measurement period adjustments, increase in intangible assets										30
Intangible assets				90
Ondot | Customer relationships
Business Acquisition [Line Items]
Measurement period adjustments, increase in intangible assets										$ 15
Intangible assets				$ 35
SpendLabs and Radius8
Business Acquisition [Line Items]
Payments for acquisitions of businesses								$ 46
Intangible assets								19
Goodwill								$ 28
MerchantPro, Bypass, and Inlet
Business Acquisition [Line Items]
Payments for acquisitions of businesses						$ 167
Acquired cash						2
Earn-out provisions estimated fair value						45
Intangible assets						81
Goodwill						90
Goodwill, expected tax deductible amount						36
Net assumed liabilities						4
MerchantPro, Bypass, and Inlet | Acquired software and technology
Business Acquisition [Line Items]
Intangible assets						14
MerchantPro, Bypass, and Inlet | Customer relationships
Business Acquisition [Line Items]
Intangible assets						$ 32