Goodwill and Other Intangible Assets (Details) - Other Intangible Assets - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Other intangible assets by major asset class
Intangible assets subject to amortization, gross carrying amount	$ 306	$ 304
Intangible assets subject to amortization, accumulated amortization	215	200
Intangible assets subject to amortization, net	91	104
Intangible assets not subject to amortization	226	226
Total other intangible assets, gross carrying amount	532	530
Total other intangible assets, net	317	330
Amortization expense of intangible assets	14	15	$ 17
Estimated intangible asset amortization expense, 2021	14
Estimated intangible asset amortization expense, 2022	13
Estimated intangible asset amortization expense, 2023	13
Estimated intangible asset amortization expense, 2024	12
Estimated intangible asset amortization expense, 2025	12
Customer-related [Member]
Other intangible assets by major asset class
Intangible assets subject to amortization, gross carrying amount	101	99
Intangible assets subject to amortization, accumulated amortization	31	21
Intangible assets subject to amortization, net	70	78
Contract-based [Member]
Other intangible assets by major asset class
Intangible assets subject to amortization, gross carrying amount	205	205
Intangible assets subject to amortization, accumulated amortization	184	179
Intangible assets subject to amortization, net	21	$ 26
Insurance Contracts Acquired in Business Combination [Member]
Other intangible assets by major asset class
Estimated intangible asset amortization expense, 2021	4
Estimated intangible asset amortization expense, 2022	3
Estimated intangible asset amortization expense, 2023	3
Estimated intangible asset amortization expense, 2024	2
Estimated intangible asset amortization expense, 2025	$ 2