Business Combinations (Details) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2020 USD ($)	Dec. 31, 2020 USD ($)
Business Acquisition [Line Items]
Business Combination, Consideration Transferred		$ 81
Distribution Relationships
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life	15 years
Non-compete Agreements
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life	5 years
Trade Names
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life	8 years
Distribution Relationships
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Gross	$ 33	33
Non-compete Agreements
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Gross	1	1
Trade Names
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Gross	1	1
Xchange
Business Acquisition [Line Items]
Business Combination, Consideration Transferred	81
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents	2	2
BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedrResstrictedCash	4	4
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	36	36
Goodwill, Acquired During Period	46
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets	8	8
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	96	96
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Accounts Payable	8	8
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	8	8
Redeemable Noncontrolling Interest, Equity, Carrying Amount	7	7
Business Acquisition, Goodwill, Expected Tax Deductible Amount	36	36
2018	3	3
2019	3	3
2020	3	3
2021	3	3
2022	3	3
Thereafter	$ 22	$ 22