Derivatives - Derivative Assets and Collateral Received (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Derivative [Line Items]
Gross amounts of recognized assets	$ 333	$ 327
Gross amounts offset in the Balance Sheets	0	0
Net amounts of assets presented in the Balance Sheets	333	327
Derivative liabilities available for offset	(85)	(83)
Collateral received	(226)	(210)
Net amount	22	34
Derivative assets not subject to master netting agreements (prior year less than)	3	1
Interest rate derivative contracts
Derivative [Line Items]
Gross amounts of recognized assets	310	320
Gross amounts offset in the Balance Sheets	0	0
Net amounts of assets presented in the Balance Sheets	310	320
Derivative liabilities available for offset	(77)	(79)
Collateral received	(226)	(209)
Net amount	7	32
Forward contracts
Derivative [Line Items]
Gross amounts of recognized assets	23	7
Gross amounts offset in the Balance Sheets	0	0
Net amounts of assets presented in the Balance Sheets	23	7
Derivative liabilities available for offset	(8)	(4)
Collateral received	0	(1)
Net amount	$ 15	$ 2