Investment Securities - Summary of Remaining Contractual Principal Maturities for Available-for-Sale Securities (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-Sale, Fair Value, Fiscal Year Maturity [Abstract]
Total	$ 26,069	$ 27,221
One Year or Less	1,084
After One Year to Five Years	14,784
After Five Years to Ten Years	2,963
After Ten Years	7,238
U.S. Treasury securities
Debt Securities, Available-for-Sale, Fair Value, Fiscal Year Maturity [Abstract]
Total	16,135	15,850
One Year or Less	983
After One Year to Five Years	14,373
After Five Years to Ten Years	779
After Ten Years	0
U.S. agency debentures
Debt Securities, Available-for-Sale, Fair Value, Fiscal Year Maturity [Abstract]
Total	101	196
One Year or Less	0
After One Year to Five Years	33
After Five Years to Ten Years	68
After Ten Years	0
Foreign government debt securities
Debt Securities, Available-for-Sale, Fair Value, Fiscal Year Maturity [Abstract]
Total	1,088	61
One Year or Less	101
After One Year to Five Years	52
After Five Years to Ten Years	935
After Ten Years	0
Agency-issued MBS
Debt Securities, Available-for-Sale, Fair Value, Fiscal Year Maturity [Abstract]
Total	6,603	8,589
One Year or Less	0
After One Year to Five Years	0
After Five Years to Ten Years	43
After Ten Years	6,560
Agency-issued CMO—fixed rate
Debt Securities, Available-for-Sale, Fair Value, Fiscal Year Maturity [Abstract]
Total	678	982
One Year or Less	0
After One Year to Five Years	0
After Five Years to Ten Years	0
After Ten Years	678
Agency-issued CMBS
Debt Securities, Available-for-Sale, Fair Value, Fiscal Year Maturity [Abstract]
Total	1,464	$ 1,543
One Year or Less	0
After One Year to Five Years	326
After Five Years to Ten Years	1,138
After Ten Years	$ 0
Lower Limit | Available-for-sale Securities
Investments Classified By Contractual Maturity Date [Line Items]
Mortgage-backed securities contractual maturities (in years)	10 years
Upper Limit | Available-for-sale Securities
Investments Classified By Contractual Maturity Date [Line Items]
Mortgage-backed securities contractual maturities (in years)	30 years