Derivative Instruments and Hedging Activities - Derivative Assets and Liabilities at Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Derivatives, Fair Value [Line Items]
Notional or contractual amount	$ 213,069	$ 232,327
Derivative assets, gross amount	2,690	3,415
Derivative liabilities, gross amount	1,868	1,518
Derivative asset, netting adjustments	(542)	(1,148)
Derivative liability, netting adjustments	(544)	(739)
Total derivative assets	2,148	2,267
Total derivative liabilities	1,324	779
Net valuation allowance on derivative assets and liabilities for non-performance risk	11	31
Derivatives designated as accounting hedges
Derivatives, Fair Value [Line Items]
Notional or contractual amount	111,618	138,724
Derivative assets, gross amount	326	921
Derivative liabilities, gross amount	39	368
Derivatives designated as accounting hedges | Interest rate contracts
Derivatives, Fair Value [Line Items]
Notional or contractual amount	102,059	129,499
Derivative assets, gross amount	246	757
Derivative liabilities, gross amount	19	11
Derivatives designated as accounting hedges | Interest rate contracts | Fair value hedges
Derivatives, Fair Value [Line Items]
Notional or contractual amount	49,659	47,349
Derivative assets, gross amount	2	9
Derivative liabilities, gross amount	3	10
Derivatives designated as accounting hedges | Interest rate contracts | Cash flow hedges
Derivatives, Fair Value [Line Items]
Notional or contractual amount	52,400	82,150
Derivative assets, gross amount	244	748
Derivative liabilities, gross amount	16	1
Derivatives designated as accounting hedges | Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Notional or contractual amount	9,559	9,225
Derivative assets, gross amount	80	164
Derivative liabilities, gross amount	20	357
Derivatives designated as accounting hedges | Foreign exchange contracts | Fair value hedges
Derivatives, Fair Value [Line Items]
Notional or contractual amount	1,421	1,527
Derivative assets, gross amount	13	164
Derivative liabilities, gross amount	0	0
Derivatives designated as accounting hedges | Foreign exchange contracts | Cash flow hedges
Derivatives, Fair Value [Line Items]
Notional or contractual amount	4,679	4,582
Derivative assets, gross amount	24	0
Derivative liabilities, gross amount	20	161
Derivatives designated as accounting hedges | Foreign exchange contracts | Net investment hedges
Derivatives, Fair Value [Line Items]
Notional or contractual amount	3,459	3,116
Derivative assets, gross amount	43	0
Derivative liabilities, gross amount	0	196
Derivatives not designated as accounting hedges
Derivatives, Fair Value [Line Items]
Notional or contractual amount	101,451	93,603
Derivative assets, gross amount	2,364	2,494
Derivative liabilities, gross amount	1,829	1,150
Derivatives not designated as accounting hedges | Customer accommodation
Derivatives, Fair Value [Line Items]
Notional or contractual amount	97,524	90,007
Derivative assets, gross amount	2,329	2,422
Derivative liabilities, gross amount	1,797	1,088
Derivatives not designated as accounting hedges | Interest rate contracts | Customer accommodation
Derivatives, Fair Value [Line Items]
Notional or contractual amount	71,724	68,459
Derivative assets, gross amount	620	1,429
Derivative liabilities, gross amount	194	198
Derivatives not designated as accounting hedges | Interest rate contracts | Other interest rate exposures
Derivatives, Fair Value [Line Items]
Notional or contractual amount	1,899	1,770
Derivative assets, gross amount	33	71
Derivative liabilities, gross amount	25	56
Derivatives not designated as accounting hedges | Foreign exchange contracts | Customer accommodation
Derivatives, Fair Value [Line Items]
Notional or contractual amount	3,779	4,677
Derivative assets, gross amount	40	58
Derivative liabilities, gross amount	42	70
Derivatives not designated as accounting hedges | Commodity contracts | Customer accommodation
Derivatives, Fair Value [Line Items]
Notional or contractual amount	22,021	16,871
Derivative assets, gross amount	1,669	935
Derivative liabilities, gross amount	1,561	820
Derivatives not designated as accounting hedges | Other contracts
Derivatives, Fair Value [Line Items]
Notional or contractual amount	2,028	1,826
Derivative assets, gross amount	2	1
Derivative liabilities, gross amount	$ 7	$ 6