Debt (Schedule of Short-term Debt) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Short-term Debt [Line Items]
Federal Home Loan Bank	$ 700	$ 1,900
Other	755	499
Total short-term borrowings	1,455	2,399
Cash collateral	$ 4	1
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	700	1,900
Other	755	499
Total short-term borrowings	1,455	$ 2,399
Secured debt | Agency Mortgage-Backed Residential Debt Securities Maturing Within 30 Days
Short-term Debt [Line Items]
Other	493
Secured debt | Agency Mortgage-Backed Residential Debt Securities Maturing Within 31 To 60 Days
Short-term Debt [Line Items]
Other	$ 262