Derivatives - Offsetting Derivative Assets and Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Derivative [Line Items]
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other Investments	Other Investments
Asset Derivatives	$ 71	$ 57
Derivative assets	47	(1)
Gross Amounts of Recognized (Liabilities)	(46)	(50)
Derivative Liability	(22)	8
Other liabilities
Derivative [Line Items]
Derivative, Collateral, Obligation to Return Cash	(15)	22
Gross Amounts of Recognized (Liabilities)	(46)	(50)
Gross Amounts Offset in the Statement of Financial Position, liabilities	(39)	(36)
Derivative Liability	(22)	8
Financial Collateral (Received)	(6)	(13)
Net amount, liabilities	(1)	(1)
Other investments
Derivative [Line Items]
Asset Derivatives	71	57
Gross Amounts Offset in the Statement of Financial Position, assets	67	55
Derivative assets	47	(1)
Derivative, Collateral, Obligation to Return Cash	43	(3)
Financial Collateral Pledged	0	0
Net Amount, assets	$ 4	$ 2