Derivative Instruments - Summary of Asset and Liability Management Derivative Positions of Company (Detail) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Derivative [Line Items]
Notional Value	$ 867,900
Cash Flow Hedges [Member]
Derivative [Line Items]
Notional Value		$ 0
Asset and Liability Management Positions [Member]
Derivative [Line Items]
Notional Value	103,442	116,117
Fair Value, Assets	791	350
Fair Value, Liabilities	622	409
Asset and Liability Management Positions [Member] | Other Derivatives [Member]
Derivative [Line Items]
Notional Value	2,289	1,792
Fair Value, Assets	13
Fair Value, Liabilities	188	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	10,570	9,653
Fair Value, Liabilities	1
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	12,154	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	7,211	9,322
Fair Value, Assets	42	10
Fair Value, Liabilities	160	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	16,777	29,348
Fair Value, Assets	341	25
Fair Value, Liabilities	102	27
Asset and Liability Management Positions [Member] | Other Economic Hedges [Member] | Interest Rate Contracts [Member] | Options [Member] | Purchased [Member]
Derivative [Line Items]
Notional Value	11,350	18,570
Fair Value, Assets	357	256
Fair Value, Liabilities	2
Asset and Liability Management Positions [Member] | Other Economic Hedges [Member] | Interest Rate Contracts [Member] | Options [Member] | Written [Member]
Derivative [Line Items]
Notional Value	9,443	9,662
Fair Value, Assets	4	52
Fair Value, Liabilities	127	231
Asset and Liability Management Positions [Member] | Other Economic Hedges [Member] | Foreign Exchange Forward Contracts [Member]
Derivative [Line Items]
Notional Value	665	735
Fair Value, Assets	9	2
Fair Value, Liabilities	4	6
Asset and Liability Management Positions [Member] | Other Economic Hedges [Member] | Equity Contracts [Member]
Derivative [Line Items]
Notional Value	181	209
Fair Value, Assets		5
Fair Value, Liabilities	14
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	10,800
Fair Value, Liabilities	24
Asset and Liability Management Positions [Member] | Net Investment Hedges [Member] | Foreign Exchange Forward Contracts [Member]
Derivative [Line Items]
Notional Value	782	793
Fair Value, Assets	$ 25
Fair Value, Liabilities		$ 4