Investments - Debt Securities by Maturity (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Amortized Cost
Less than one year	$ 1,205
One year through five years	6,965
After five years through ten years	4,733
Greater than ten years	4,332
Amortized Cost	22,174	$ 19,396
Fair Value
Less than one year	1,218
One year through five years	7,142
After five years through ten years	4,910
Greater than ten years	4,993
Total	23,240	21,188
Residential mortgage-backed securities
Amortized Cost
Debt securities, maturity, without single maturity date	870
Amortized Cost	870	673
Fair Value
Debt securities, maturity, without single maturity date	875
Total	875	705
Commercial mortgage-backed securities
Amortized Cost
Debt securities, maturity, without single maturity date	1,278
Amortized Cost	1,278	962
Fair Value
Debt securities, maturity, without single maturity date	1,310
Total	1,310	1,046
Other asset-backed securities
Amortized Cost
Debt securities, maturity, without single maturity date	2,791
Amortized Cost	2,791	2,369
Fair Value
Debt securities, maturity, without single maturity date	2,792
Total	$ 2,792	$ 2,403