Derivative Instruments - Summary of Asset and Liability Management Derivative Positions of Company (Detail) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Derivative [Line Items]
Notional Value	$ 800,600
Cash Flow Hedges [Member]
Derivative [Line Items]
Notional Value		$ 0
Asset and Liability Management Positions [Member]
Derivative [Line Items]
Notional Value	93,147	116,117
Fair Value, Assets	361	350
Fair Value, Liabilities	271	409
Asset and Liability Management Positions [Member] | Other Derivatives [Member]
Derivative [Line Items]
Notional Value	2,344	1,792
Fair Value, Assets	2
Fair Value, Liabilities	81	125
Asset and Liability Management Positions [Member] | Other Economic Hedges [Member] | Interest Rate Contracts [Member] | Receive Fixed/Pay Floating Swaps [Member]
Derivative [Line Items]
Notional Value	11,420	9,653
Asset and Liability Management Positions [Member] | Other Economic Hedges [Member] | Interest Rate Contracts [Member] | Pay Fixed/Receive Floating Swaps [Member]
Derivative [Line Items]
Notional Value	12,481	7,033
Asset and Liability Management Positions [Member] | Other Economic Hedges [Member] | Interest Rate Contracts [Member] | Futures and Forwards [Member] | Purchased [Member]
Derivative [Line Items]
Notional Value	11,040	9,322
Fair Value, Assets	30	10
Fair Value, Liabilities	63	16
Asset and Liability Management Positions [Member] | Other Economic Hedges [Member] | Interest Rate Contracts [Member] | Futures and Forwards [Member] | Written [Member]
Derivative [Line Items]
Notional Value	9,811	29,348
Fair Value, Assets	34	25
Fair Value, Liabilities	31	27
Asset and Liability Management Positions [Member] | Other Economic Hedges [Member] | Interest Rate Contracts [Member] | Options [Member] | Purchased [Member]
Derivative [Line Items]
Notional Value	7,480	18,570
Fair Value, Assets	260	256
Asset and Liability Management Positions [Member] | Other Economic Hedges [Member] | Interest Rate Contracts [Member] | Options [Member] | Written [Member]
Derivative [Line Items]
Notional Value	7,208	9,662
Fair Value, Assets	20	52
Fair Value, Liabilities	93	231
Asset and Liability Management Positions [Member] | Other Economic Hedges [Member] | Foreign Exchange Forward Contracts [Member]
Derivative [Line Items]
Notional Value	852	735
Fair Value, Assets	5	2
Fair Value, Liabilities	2	6
Asset and Liability Management Positions [Member] | Other Economic Hedges [Member] | Equity Contracts [Member]
Derivative [Line Items]
Notional Value	186	209
Fair Value, Assets	4	5
Fair Value, Liabilities	0
Asset and Liability Management Positions [Member] | Fair Value Hedges [Member] | Interest Rate Contracts [Member] | Receive Fixed/Pay Floating Swaps [Member]
Derivative [Line Items]
Notional Value	17,400	12,350
Asset and Liability Management Positions [Member] | Fair Value Hedges [Member] | Interest Rate Contracts [Member] | Pay Fixed/Receive Floating Swaps [Member]
Derivative [Line Items]
Notional Value	3,820	16,650
Asset and Liability Management Positions [Member] | Cash Flow Hedges [Member] | Interest Rate Contracts [Member] | Receive Fixed/Pay Floating Swaps [Member]
Derivative [Line Items]
Notional Value	8,300
Asset and Liability Management Positions [Member] | Net Investment Hedges [Member] | Foreign Exchange Forward Contracts [Member]
Derivative [Line Items]
Notional Value	805	793
Fair Value, Assets	6
Fair Value, Liabilities	$ 1	$ 4