Goodwill and Other Intangible Assets (Details) - Other Intangible Assets - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Other intangible assets by major asset class
Intangible assets subject to amortization, gross carrying amount	$ 309		$ 309		$ 306
Intangible assets subject to amortization, accumulated amortization	226		226		215
Intangible assets subject to amortization, net	83		83		91
Intangible assets not subject to amortization	226		226		226
Total other intangible assets, gross carrying amount	535		535		532
Total other intangible assets, net	309		309		317
Amortization expense of intangible assets	4	$ 4	11	$ 11
Estimated intangible asset amortization expense, remainder of 2021	3		3
Estimated intangible asset amortization expense, 2022	14		14
Estimated intangible asset amortization expense, 2023	13		13
Estimated intangible asset amortization expense, 2024	12		12
Estimated intangible asset amortization expense, 2025	12		12
Customer-related [Member]
Other intangible assets by major asset class
Intangible assets subject to amortization, gross carrying amount	104		104		101
Intangible assets subject to amortization, accumulated amortization	39		39		31
Intangible assets subject to amortization, net	65		65		70
Contract-based [Member]
Other intangible assets by major asset class
Intangible assets subject to amortization, gross carrying amount	205		205		205
Intangible assets subject to amortization, accumulated amortization	187		187		184
Intangible assets subject to amortization, net	18		18		$ 21
Insurance Contracts Acquired in Business Combination [Member]
Other intangible assets by major asset class
Estimated intangible asset amortization expense, remainder of 2021	1		1
Estimated intangible asset amortization expense, 2022	3		3
Estimated intangible asset amortization expense, 2023	3		3
Estimated intangible asset amortization expense, 2024	2		2
Estimated intangible asset amortization expense, 2025	$ 2		$ 2