Investments - Summary of Debt Securities with a Decline in Fair Value (Details) $ in Millions	Jun. 30, 2022 USD ($) position	Dec. 31, 2021 USD ($) position
More than one year
Total Fair Value	$ 10,443	$ 3,890
Total Amortized Cost	11,644	4,021
Total Unrealized Depreciation	$ (1,201)	$ (131)
Total Number of Issues | position	4,589	1,886
Investment grade | Debt securities
One year or less
Fair Value	$ 8,378	$ 2,785
Amortized Cost	9,258	2,861
Unrealized Depreciation	$ (880)	$ (76)
Number of Issues | position	2,695	909
More than one year
Fair Value	$ 750	$ 382
Amortized Cost	916	412
Unrealized Depreciation	$ (166)	$ (30)
Number of Issues | position	355	143
Below investment grade | Debt securities
One year or less
Fair Value	$ 1,124	$ 561
Amortized Cost	1,252	578
Unrealized Depreciation	$ (128)	$ (17)
Number of Issues | position	1,405	781
More than one year
Fair Value	$ 191	$ 162
Amortized Cost	218	170
Unrealized Depreciation	$ (27)	$ (8)
Number of Issues | position	134	53