Investments (held-to-maturity credit quality indicator) (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt Securities, Held-to-maturity	$ 9,852	$ 10,153
Fixed Maturities Percent of Total Amortized cost	100.00%	100.00%
Standard & Poor's, AAA Rating [Member]
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt Securities, Held-to-maturity	$ 2,021	$ 2,089
Fixed Maturities Percent of Total Amortized cost	21.00%	21.00%
Standard & Poor's, AA Rating [Member]
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt Securities, Held-to-maturity	$ 5,210	$ 5,303
Fixed Maturities Percent of Total Amortized cost	52.00%	52.00%
Standard & Poor's, A Rating [Member]
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt Securities, Held-to-maturity	$ 1,922	$ 1,964
Fixed Maturities Percent of Total Amortized cost	20.00%	19.00%
Standard & Poor's, BBB Rating [Member]
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt Securities, Held-to-maturity	$ 676	$ 773
Fixed Maturities Percent of Total Amortized cost	7.00%	8.00%
Standard & Poor's, BB Rating [Member]
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt Securities, Held-to-maturity	$ 23	$ 23
Fixed Maturities Percent of Total Amortized cost	0.00%	0.00%
Other [Member]
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt Securities, Held-to-maturity	$ 0	$ 1
Fixed Maturities Percent of Total Amortized cost	0.00%	0.00%