Investments (Rollforward of expected credit losses HTM) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Debt Securities, Held-to-maturity, Allowance for Credit Loss	$ 34	$ 37	$ 34	$ 37	$ 34	$ 35	$ 43	$ 44
Debt Securities, Held-to-maturity, Allowance for Credit Loss, Period Increase (Decrease)	1	0	1	0
Debt Securities, Held-to-maturity, Allowance for Credit Loss, Recovery	$ (1)	$ (6)	$ (2)	$ (7)