Derivative Financial Instruments - Summary of Aggregate Contractual or Notional Amounts and Estimated Fair Values (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Derivative [Line Items]
Contractual/ Notional Amount	$ 7,161	$ 6,926
Total derivative assets	83	11
Amounts netted	(21)	(6)
Net derivatives	62	5
Total derivative liabilities	(49)	(156)
Amounts netted	21	6
Net derivative liabilities	(28)	(150)
Hedging instruments
Derivative [Line Items]
Contractual/ Notional Amount	7,126	6,797
Total derivative assets	83	8
Total derivative liabilities	(49)	(156)
Hedging instruments | Interest rate swaps
Derivative [Line Items]
Contractual/ Notional Amount	6,875	6,475
Total derivative assets	83	8
Total derivative liabilities	(44)	(150)
Hedging instruments | Foreign currency forwards
Derivative [Line Items]
Contractual/ Notional Amount	251	322
Total derivative assets	0	0
Total derivative liabilities	(5)	(6)
Non-hedging instruments
Derivative [Line Items]
Contractual/ Notional Amount	35	129
Total derivative assets	0	3
Total derivative liabilities	0	0
Non-hedging instruments | Interest rate swaps
Derivative [Line Items]
Contractual/ Notional Amount		5
Total derivative assets		0
Total derivative liabilities		0
Non-hedging instruments | Futures/Forwards
Derivative [Line Items]
Contractual/ Notional Amount	35	124
Total derivative assets	0	3
Total derivative liabilities	$ 0	$ 0