v3.22.0.1
Trading Cash Instruments - Cash Instruments, Level 3 Rollforward (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Other Cash Instruments [Member]    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value, Beginning Balance $ 106  
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value, Ending Balance   $ 106
Trading Cash Instruments Assets [Member]    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value, Beginning Balance 1,237 1,242
Net realized gains / (losses) 80 66
Net unrealized gains / (losses) 52 (143)
Purchases 1,241 796
Sales (456) (411)
Settlements (273) (266)
Transfers into level 3 272 156
Transfers out of level 3 (264) (203)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value, Ending Balance 1,889 1,237
Trading Cash Instruments Assets [Member] | Loans and Securities Backed by Commercial Real Estate [Member]    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value, Beginning Balance 203 191
Net realized gains / (losses) 7 11
Net unrealized gains / (losses) (16) (33)
Purchases 67 110
Sales (31) (19)
Settlements (18) (64)
Transfers into level 3 14 25
Transfers out of level 3 (89) (18)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value, Ending Balance 137 203
Trading Cash Instruments Assets [Member] | Loans and Securities Backed by Residential Real Estate [Member]    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value, Beginning Balance 131 231
Net realized gains / (losses) 5 11
Net unrealized gains / (losses) 19 23
Purchases 68 69
Sales (44) (80)
Settlements (35) (40)
Transfers into level 3 28 5
Transfers out of level 3 (20) (88)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value, Ending Balance 152 131
Trading Cash Instruments Assets [Member] | Corporate debt instruments [Member]    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value, Beginning Balance 797 692
Net realized gains / (losses) 57 47
Net unrealized gains / (losses) 28 (118)
Purchases 894 551
Sales (330) (233)
Settlements (182) (146)
Transfers into level 3 207 96
Transfers out of level 3 (153) (92)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value, Ending Balance 1,318 797
Trading Cash Instruments Assets [Member] | Other Cash Instruments [Member]    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value, Beginning Balance 106 128
Net realized gains / (losses) 11 (3)
Net unrealized gains / (losses) 21 (15)
Purchases 212 66
Sales (51) (79)
Settlements (38) (16)
Transfers into level 3 23 30
Transfers out of level 3 (2) (5)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value, Ending Balance 282 106
Trading Cash Instruments Liabilities [Member]    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value, Beginning Balance (80) (273)
Net realized gains / (losses) 6 0
Net unrealized gains / (losses) (5) (15)
Purchases 36 34
Sales (64) (38)
Settlements 13 9
Transfers into level 3 (16) (27)
Transfers out of level 3 6 230
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value, Ending Balance $ (104) $ (80)