Fair Value Measurements - Changes in Fair Value of Level 3 Assets and Liabilities (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Derivatives liability
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total liabilities, beginning balance	$ (106)
Total liabilities, ending balance	(102)	$ (106)
Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total assets, beginning balance	207	122
Assets, Total Realized/Unrealized Gains (Losses) Included in Earnings	77	56
Assets, Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss)	2	(2)
Assets, Purchases	11	54
Assets, Issuances	180	0
Assets, Settlements	(192)	(95)
Assets, Transfers Into Level 3	9	164
Assets Transfers out of Level 3	(54)	(92)
Total assets, ending balance	240	207
Assets, Current Period Unrealized Gains (Losses) Still Held Included in Earnings	22	2
Assets, Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income (Loss)	2	(2)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total liabilities, beginning balance	(2,444)	(2,212)
Total Realized/Unrealized Gains (Losses) Included in Earnings	(303)	(271)
Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income	(4)	(8)
Purchases	0	0
Issuances	(2,612)	(2,636)
Settlements	1,471	1,414
Transfers Into Level 3	(1,655)	(465)
Transfers Out of Level 3	2,816	1,734
Total liabilities, ending balance	(2,731)	(2,444)
Current Period Unrealized Gains (Losses) Still Held Included in Earnings	(344)	(54)
Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income (Loss)	$ (4)	$ (8)
Fair Value, Liability, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Net income	Net income
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Net income	Net income
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Net income	Net income
Level 3 | Equity contracts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Derivatives, net, Beginning Balance	$ (18)	$ 21
Derivatives, net, Total Realized/Unrealized Gains (Losses) Included in Earnings	157	88
Derivatives, net, Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income	0	0
Derivatives, net, Purchases	0	0
Derivatives, net, Issuances	0	0
Derivatives, net, Settlements	(65)	(50)
Derivatives, net, Transfers into Level 3	(17)	(4)
Derivatives, net, Transfers out of Level 3	(46)	(73)
Derivatives, net, Ending Balance	11	(18)
Derivatives, net, Current Period Unrealized Gains (Losses) Still Held Included in Earnings	80	(3)
Derivatives, net, Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income (Loss)	0	0
Level 3 | Other Contracts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Derivatives, net, Beginning Balance	(26)	(35)
Derivatives, net, Total Realized/Unrealized Gains (Losses) Included in Earnings	(22)	(35)
Derivatives, net, Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income	0	0
Derivatives, net, Purchases	0	0
Derivatives, net, Issuances	0	0
Derivatives, net, Settlements	35	44
Derivatives, net, Transfers into Level 3	0	0
Derivatives, net, Transfers out of Level 3	0	0
Derivatives, net, Ending Balance	(13)	(26)
Derivatives, net, Current Period Unrealized Gains (Losses) Still Held Included in Earnings	0	0
Derivatives, net, Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income (Loss)	0	0
Asset-backed securities available-for-sale | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total assets, beginning balance	97	104
Assets, Total Realized/Unrealized Gains (Losses) Included in Earnings	0	0
Assets, Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss)	2	(2)
Assets, Purchases	0	0
Assets, Issuances	0	0
Assets, Settlements	(15)	(5)
Assets, Transfers Into Level 3	0	0
Assets Transfers out of Level 3	(8)	0
Total assets, ending balance	76	97
Assets, Current Period Unrealized Gains (Losses) Still Held Included in Earnings	0	0
Assets, Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income (Loss)	$ 2	$ (2)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other comprehensive income, net of tax	Other comprehensive income, net of tax
Derivative assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total assets, beginning balance	$ 58
Total assets, ending balance	99	$ 58
Domestic deposits | Level 3
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total liabilities, beginning balance	(291)	(293)
Total Realized/Unrealized Gains (Losses) Included in Earnings	(36)	(16)
Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income	0	(4)
Purchases	0	0
Issuances	(232)	(276)
Settlements	48	89
Transfers Into Level 3	(325)	(78)
Transfers Out of Level 3	459	287
Total liabilities, ending balance	(377)	(291)
Current Period Unrealized Gains (Losses) Still Held Included in Earnings	(70)	5
Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income (Loss)	0	(4)
Long-term debt | Level 3
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total liabilities, beginning balance	(2,153)	(1,919)
Total Realized/Unrealized Gains (Losses) Included in Earnings	(267)	(255)
Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income	(4)	(4)
Purchases	0	0
Issuances	(2,380)	(2,360)
Settlements	1,423	1,325
Transfers Into Level 3	(1,330)	(387)
Transfers Out of Level 3	2,357	1,447
Total liabilities, ending balance	(2,354)	(2,153)
Current Period Unrealized Gains (Losses) Still Held Included in Earnings	(274)	(59)
Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income (Loss)	(4)	(4)
Loans held for sale | Loans | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total assets, beginning balance	154	32
Assets, Total Realized/Unrealized Gains (Losses) Included in Earnings	(58)	3
Assets, Total Realized/Unrealized Gains (Losses) Included in Other Comprehensive Income (Loss)	0	0
Assets, Purchases	11	54
Assets, Issuances	180	0
Assets, Settlements	(147)	(84)
Assets, Transfers Into Level 3	26	168
Assets Transfers out of Level 3	0	(19)
Total assets, ending balance	166	154
Assets, Current Period Unrealized Gains (Losses) Still Held Included in Earnings	(58)	5
Assets, Current Period Unrealized Gains (Losses) Still Held Included in Other Comprehensive Income (Loss)	$ 0	$ 0