Securities - Amortized Cost and Fair Value of Asset Backed Securities (Detail) - USD ($)		Dec. 31, 2023	Dec. 31, 2022
Securities available-for-sale:
Amortized Cost		$ 27,980,000,000	$ 30,335,000,000
Allowance for Credit Losses		0	0
Unrealized Gains		26,000,000	35,000,000
Unrealized Losses		(2,310,000,000)	(3,025,000,000)
Fair Value	[1]	25,696,000,000	27,345,000,000
Securities held-to-maturity:
Amortized Cost		15,076,000,000	7,317,000,000
Allowance for Credit Losses		0	0
Unrealized Gains		47,000,000	3,000,000
Unrealized Losses		(434,000,000)	(458,000,000)
Fair Value		14,689,000,000	6,862,000,000
U.S. Treasury
Securities available-for-sale:
Amortized Cost		7,489,000,000	7,662,000,000
Allowance for Credit Losses		0	0
Unrealized Gains		22,000,000	32,000,000
Unrealized Losses		(225,000,000)	(242,000,000)
Fair Value		7,286,000,000	7,452,000,000
Securities held-to-maturity:
Amortized Cost		1,917,000,000	873,000,000
Allowance for Credit Losses		0	0
Unrealized Gains		1,000,000	0
Unrealized Losses		(18,000,000)	(15,000,000)
Fair Value		1,900,000,000	858,000,000
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises
Securities available-for-sale:
Amortized Cost		5,864,000,000	6,537,000,000
Allowance for Credit Losses		0	0
Unrealized Gains		0	0
Unrealized Losses		(845,000,000)	(1,024,000,000)
Fair Value		5,019,000,000	5,513,000,000
Securities held-to-maturity:
Amortized Cost		1,069,000,000	1,146,000,000
Allowance for Credit Losses		0	0
Unrealized Gains		0	0
Unrealized Losses		(68,000,000)	(80,000,000)
Fair Value		1,001,000,000	1,066,000,000
Collateralized Mortgage Obligations, Issued by U.S. Government Sponsored Enterprises
Securities available-for-sale:
Amortized Cost		1,436,000,000	1,549,000,000
Allowance for Credit Losses		0	0
Unrealized Gains		0	0
Unrealized Losses		(300,000,000)	(323,000,000)
Fair Value		1,136,000,000	1,226,000,000
Securities held-to-maturity:
Amortized Cost		297,000,000	358,000,000
Allowance for Credit Losses		0	0
Unrealized Gains		3,000,000	3,000,000
Unrealized Losses		(16,000,000)	(19,000,000)
Fair Value		284,000,000	342,000,000
Direct Agency Obligations U S Government Sponsored Enterprises
Securities available-for-sale:
Amortized Cost		1,719,000,000	1,807,000,000
Allowance for Credit Losses		0	0
Unrealized Gains		0	1,000,000
Unrealized Losses		(38,000,000)	(71,000,000)
Fair Value		1,681,000,000	1,737,000,000
Mortgage-backed Securities, Issued or Guaranteed by US Government Agency
Securities available-for-sale:
Amortized Cost		5,804,000,000	7,477,000,000
Allowance for Credit Losses		0	0
Unrealized Gains		1,000,000	0
Unrealized Losses		(378,000,000)	(772,000,000)
Fair Value		5,427,000,000	6,705,000,000
Securities held-to-maturity:
Amortized Cost		10,043,000,000	2,895,000,000
Allowance for Credit Losses		0	0
Unrealized Gains		43,000,000	0
Unrealized Losses		(180,000,000)	(177,000,000)
Fair Value		9,906,000,000	2,718,000,000
Collateralized Mortgage Obligations, Issued or Guaranteed by US Government Agency
Securities available-for-sale:
Amortized Cost		2,865,000,000	3,163,000,000
Allowance for Credit Losses		0	0
Unrealized Gains		0	0
Unrealized Losses		(506,000,000)	(567,000,000)
Fair Value		2,359,000,000	2,596,000,000
Securities held-to-maturity:
Amortized Cost		1,745,000,000	2,039,000,000
Allowance for Credit Losses		0	0
Unrealized Gains		0	0
Unrealized Losses		(152,000,000)	(167,000,000)
Fair Value		1,593,000,000	1,872,000,000
Direct Agency Obligations, Issued or Guaranteed by US Government Agency
Securities available-for-sale:
Amortized Cost		215,000,000	165,000,000
Allowance for Credit Losses		0	0
Unrealized Gains		3,000,000	1,000,000
Unrealized Losses		(3,000,000)	(4,000,000)
Fair Value		215,000,000	162,000,000
Home equity asset-backed securities
Securities available-for-sale:
Amortized Cost		13,000,000	16,000,000
Allowance for Credit Losses		0	0
Unrealized Gains		0	0
Unrealized Losses		(1,000,000)	(1,000,000)
Fair Value		12,000,000	15,000,000
Other asset-backed securities
Securities available-for-sale:
Amortized Cost		103,000,000	105,000,000
Allowance for Credit Losses		0	0
Unrealized Gains		0	0
Unrealized Losses		(11,000,000)	(12,000,000)
Fair Value		92,000,000	93,000,000
Foreign debt securities
Securities available-for-sale:
Amortized Cost		2,472,000,000	1,854,000,000
Allowance for Credit Losses		0	0
Unrealized Gains		0	1,000,000
Unrealized Losses		(3,000,000)	(9,000,000)
Fair Value		2,469,000,000	1,846,000,000
Obligations of U.S. states and political subdivisions
Securities held-to-maturity:
Amortized Cost		4,000,000	5,000,000
Allowance for Credit Losses		0	0
Unrealized Gains		0	0
Unrealized Losses		0	0
Fair Value		4,000,000	5,000,000
Asset-backed securities collateralized by residential mortgages
Securities held-to-maturity:
Amortized Cost		1,000,000	1,000,000
Allowance for Credit Losses		0	0
Unrealized Gains		0	0
Unrealized Losses		0	0
Fair Value		$ 1,000,000	$ 1,000,000

[1] The following table summarizes assets and liabilities related to our consolidated variable interest entities ("VIEs") at December 31, 2023 and 2022. Assets and liabilities exclude intercompany balances that eliminate in consolidation. See Note 27, "Variable Interest Entities," for additional information. At December 31,20232022(in millions)AssetsLoans, net$— $162 Other assets23 44 Total assets$23 $206 LiabilitiesInterest, taxes and other liabilities$17 $22 Total liabilities$17 $22