Investments - Carrying Values of Other Long-Term Investments (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Schedule of Investments [Line Items]
Unfunded commitments, percentage expected to fund in next fiscal year	35.00%
Other long term investments	$ 3,574
Other long-term investments		$ 2,832
Unfunded commitments	2,721
Real estate investments
Schedule of Investments [Line Items]
Other long term investments	1,152
Other long-term investments		951
Unfunded commitments	752
Securities partnerships
Schedule of Investments [Line Items]
Other long term investments	2,272
Other long-term investments		1,737
Unfunded commitments	1,969
Other
Schedule of Investments [Line Items]
Other long term investments	150
Other long-term investments		$ 144
Unfunded commitments	$ 0