Debt (Schedule of Short-term Debt) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Short-term Debt [Line Items]
Federal Home Loan Bank	$ 2,550,000,000	$ 1,900,000,000
Securities sold under agreements to repurchase	747,000,000	499,000,000
Total short-term borrowings	$ 3,297,000,000	$ 2,399,000,000
Weighted average interest rate	5.60%	4.50%
Repurchase agreements mature	30 days
Cash collateral received	$ 6,000,000
Collateral placed		$ 1,000,000
Non-cash collateral received	1,000,000	0
Unsecured debt
Short-term Debt [Line Items]
Federal Home Loan Bank	0	0
Securities sold under agreements to repurchase	0	0
Total short-term borrowings	0	0
Secured debt
Short-term Debt [Line Items]
Federal Home Loan Bank	2,550,000,000	1,900,000,000
Securities sold under agreements to repurchase	747,000,000	499,000,000
Total short-term borrowings	3,297,000,000	$ 2,399,000,000
Secured debt | Agency Mortgage-Backed Residential Debt Securities
Short-term Debt [Line Items]
Securities sold under agreements to repurchase	$ 747,000,000