Derivatives - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Derivative Instruments, Gain (Loss) [Line Items]
Collateral cash payables	$ 104		$ 184
Total trading revenues	61	$ 115
Hedged amount of foreign currency denominated loans	14		7
Derivative assets	211		323
Derivative liability	430		103
Visa Class B Shares
Derivative Instruments, Gain (Loss) [Line Items]
Derivative liabilities related to sale	18		23
Derivative valuation adjustment			19
Additional Derivative Agreements | Derivative Instruments With Adjustable Collateral Posting Thresholds
Derivative Instruments, Gain (Loss) [Line Items]
Net fair value of derivative assets with adjustable posting thresholds	10		67
Net fair value of derivative liabilities with adjustable posting thresholds	130		26
Collateral received	173		205
Securities posted collateral	30		14
Additional Derivative Agreements | Derivative Instruments With Accelerated Termination Provisions
Derivative Instruments, Gain (Loss) [Line Items]
Net fair value of derivative assets with adjustable posting thresholds	93		74
Net fair value of derivative liabilities with adjustable posting thresholds	130		30
Collateral received	233		213
Securities posted collateral	29		18
Counterparties
Derivative Instruments, Gain (Loss) [Line Items]
Collateral cash receivables	247		181
Collateral cash payables	71		102
Credit Risk Contract
Derivative Instruments, Gain (Loss) [Line Items]
Derivative asset, notional amount	215		257
Derivative liability, notional amount	692		500
Embedded Derivative Financial Instruments
Derivative Instruments, Gain (Loss) [Line Items]
Derivative assets	1		1
Derivative liability	$ 1		$ 1