Other Commitments (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Other Commitments [Line Items]
Resale agreements, unfunded commitments	$ 10,800	$ 12,000
Purchase commitment [Member] \| Debt securities [Member]
Other Commitments [Line Items]
Other commitment	18	18
Purchase commitment [Member] \| Equity securities [Member]
Other Commitments [Line Items]
Other commitment	$ 2,900	$ 3,200

Minimum amount of other commitment not otherwise specified in the taxonomy. Excludes commitments explicitly modeled in the taxonomy, including but not limited to, long-term and short-term purchase commitments, recorded and unrecorded purchase obligations, supply commitments, registration payment arrangements, leases, debt, product warranties, guarantees, environmental remediation obligations, and pensions.

No definition available.

Name:	us-gaap_OtherCommitment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant