Fair Value Disclosures (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Assets
Available-for-sale securities, debt securities	$ 1,703	$ 1,683
Recurring basis
Assets
Available-for-sale securities, debt securities	1,703	1,683
Equity Securities, FV-NI	440	405
Derivative Assets (Liabilities), at Fair Value, Net	227	(17)
Total Assets	2,370	2,088
Liabilities
Total Liabilities		17
U.S. treasury bonds
Assets
Available-for-sale securities, debt securities	10	10
U.S. treasury bonds | Recurring basis
Assets
Available-for-sale securities, debt securities	10	10
Other U.S. and non-U.S. government bonds
Assets
Available-for-sale securities, debt securities	57	59
Other U.S. and non-U.S. government bonds | Recurring basis
Assets
Available-for-sale securities, debt securities	57	59
Corporate bonds
Assets
Available-for-sale securities, debt securities	1,035	1,012
Corporate bonds | Recurring basis
Assets
Available-for-sale securities, debt securities	1,035	1,012
Asset-backed securities
Assets
Available-for-sale securities, debt securities	148	159
Asset-backed securities | Recurring basis
Assets
Available-for-sale securities, debt securities	148	159
U.S. governmental agency | Recurring basis
Assets
Available-for-sale securities, debt securities	349	374
Residential
Assets
Available-for-sale securities, debt securities	4	5
Residential | Recurring basis
Assets
Available-for-sale securities, debt securities	4	5
Commercial
Assets
Available-for-sale securities, debt securities	100	64
Commercial | Recurring basis
Assets
Available-for-sale securities, debt securities	100	64
Large capitalization value | Recurring basis
Assets
Equity Securities, FV-NI	196	199
Smaller company growth | Recurring basis
Assets
Equity Securities, FV-NI	86	58
REIT | Recurring basis
Assets
Equity Securities, FV-NI	158	148
Level 1 | Recurring basis
Assets
Available-for-sale securities, debt securities	10	10
Equity Securities, FV-NI	282	257
Total Assets	292	267
Level 1 | U.S. treasury bonds | Recurring basis
Assets
Available-for-sale securities, debt securities	10	10
Level 1 | Large capitalization value | Recurring basis
Assets
Equity Securities, FV-NI	196	199
Level 1 | Smaller company growth | Recurring basis
Assets
Equity Securities, FV-NI	86	58
Level 2 | Recurring basis
Assets
Available-for-sale securities, debt securities	1,693	1,673
Derivative Assets (Liabilities), at Fair Value, Net	227	(17)
Total Assets	1,920	1,673
Liabilities
Total Liabilities		17
Level 2 | Other U.S. and non-U.S. government bonds | Recurring basis
Assets
Available-for-sale securities, debt securities	57	59
Level 2 | Corporate bonds | Recurring basis
Assets
Available-for-sale securities, debt securities	1,035	1,012
Level 2 | Asset-backed securities | Recurring basis
Assets
Available-for-sale securities, debt securities	148	159
Level 2 | U.S. governmental agency | Recurring basis
Assets
Available-for-sale securities, debt securities	349	374
Level 2 | Residential | Recurring basis
Assets
Available-for-sale securities, debt securities	4	5
Level 2 | Commercial | Recurring basis
Assets
Available-for-sale securities, debt securities	100	64
Fair Value Measured on Net Asset Value (NAV) | Recurring basis
Assets
Equity Securities, FV-NI	158	148
Total Assets	158	148
Fair Value Measured on Net Asset Value (NAV) | REIT | Recurring basis
Assets
Equity Securities, FV-NI	158	148
Financial Products | Level 3 | Nonrecurring basis
Assets and liabilities measured on a recurring basis at fair value
Loans carried at fair value	$ 150	$ 243