Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Intangible assets	$ 364		$ 364		$ 409
Amortization of intangible assets	11	$ 14	44	$ 41
2019	10		10
2020	36		36
2021	33		33
2022	31		31
2023	28		28
Thereafter	226		226
Insurance Intangible Asset [Member]
Intangible Assets, Gross (Excluding Goodwill)	1,277		1,277		1,281
Finite-Lived Intangible Assets, Accumulated Amortization	947		947		908
Intangible assets	330		330		373
Amortization of intangible assets	10	14	42	41
2019	9		9
2020	34		34
2021	31		31
2022	28		28
2023	25		25
Thereafter	203		$ 203
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			7 years 4 months 24 days
Other Intangible Assets
Intangible Assets, Gross (Excluding Goodwill)	36		$ 36		36
Finite-Lived Intangible Assets, Accumulated Amortization	2		2		0
Intangible assets	34		34		$ 36
Amortization of intangible assets	1	$ 0	2	$ 0
2019	1		1
2020	3		3
2021	3		3
2022	3		3
2023	3		3
Thereafter	$ 22		$ 22
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	6 years 8 months 12 days

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount of amortization for asset, excluding financial asset and goodwill, lacking physical substance with finite life expected to be recognized after fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of amortization for assets, excluding financial assets and goodwill, lacking physical substance with finite life expected to be recognized in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of amortization for assets, excluding financial assets and goodwill, lacking physical substance with finite life expected to be recognized in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of amortization for assets, excluding financial assets and goodwill, lacking physical substance with finite life expected to be recognized in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount before accumulated amortization of intangible assets, excluding goodwill.

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Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges.

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