Debt (Schedule of Short-term Debt) (Details) - USD ($)	6 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Short-term Debt [Line Items]
Federal Home Loan Bank	$ 1,200,000,000	$ 1,900,000,000
Other	994,000,000	499,000,000
Total short-term borrowings	2,194,000,000	2,399,000,000
Cash collateral placed	3,000,000	1,000,000
Cash collateral received	$ 2,000,000	0
Agency Mortgage-Backed Residential Debt Securities Maturing Within 30 Days
Short-term Debt [Line Items]
Repurchase agreements mature	30 days
Minimum | Agency Mortgage-Backed Residential Debt Securities Maturing Within 31 To 60 Days
Short-term Debt [Line Items]
Repurchase agreements mature	31 days
Maximum | Agency Mortgage-Backed Residential Debt Securities Maturing Within 31 To 60 Days
Short-term Debt [Line Items]
Repurchase agreements mature	60 days
Unsecured debt
Short-term Debt [Line Items]
Federal Home Loan Bank	$ 0	0
Other	0	0
Total short-term borrowings	0	0
Secured debt
Short-term Debt [Line Items]
Federal Home Loan Bank	1,200,000,000	1,900,000,000
Other	994,000,000	499,000,000
Total short-term borrowings	2,194,000,000	$ 2,399,000,000
Secured debt | Agency Mortgage-Backed Residential Debt Securities Maturing Within 30 Days
Short-term Debt [Line Items]
Other	742,000,000
Secured debt | Agency Mortgage-Backed Residential Debt Securities Maturing Within 31 To 60 Days
Short-term Debt [Line Items]
Other	$ 252,000,000