Debt Obligations - Senior Secured Credit Facility (Details)	3 Months Ended	9 Months Ended
	Sep. 30, 2021 USD ($)	Sep. 30, 2021 USD ($) Rate	Feb. 16, 2021 USD ($)	Dec. 31, 2020 USD ($)
Debt Instrument [Line Items]
Senior secured bridge facility			$ 1,000,000,000
Senior secured incremental term loan A facility	$ 1,505,000,000	$ 1,505,000,000
Senior secured incremental term loan B facility	750,000,000	750,000,000
Revolving credit facility under senior secured credit facility	1,100,000,000	1,100,000,000
Letters of credit outstanding	26,000,000	26,000,000
Converted Portion of Term Loan A	200,000,000	200,000,000
Aggregate Principal Amount of Term Loan A Facility	1,305,000,000	1,305,000,000
Long-term debt	$ 5,534,000,000	$ 5,534,000,000		$ 3,270,000,000
Quarterly Payment of Term Loan Principal Amount		0.25%
Quarterly Payment of Term Loan A facility [Abstract]		1.875%
Increase in Maximum Permitted Leverage Ratio due to Material Acquisitions	0.25	0.25
Debt Related Commitment Fees and Debt Issuance Costs	$ 0	$ 19,000,000
Available additional amount of incremental term loan commitment	$ 150,000,000	$ 150,000,000
Period One
Debt Instrument [Line Items]
Debt consolidated leverage ratio	5.50	5.50
Period Two
Debt Instrument [Line Items]
Debt consolidated leverage ratio	5.25	5.25
Period Three
Debt Instrument [Line Items]
Debt consolidated leverage ratio	4.75	4.75
Secured Debt | Minimum
Debt Instrument [Line Items]
Debt Instrument, Fee		0.15
Secured Debt | Maximum
Debt Instrument [Line Items]
Debt Instrument, Fee		0.45
Secured Debt | Term Loan A and Revolving Facility
Debt Instrument [Line Items]
Debt basis spread on variable rate | Rate		1.50%
Debt Instrument, Base Rate		0.00%
Secured Debt | Term Loan B Facility [Member]
Debt Instrument [Line Items]
Debt basis spread on variable rate | Rate		1.50%
Secured Debt | Federal Funds Rate | Term Loan A and Revolving Facility
Debt Instrument [Line Items]
Debt basis spread on variable rate		0.50%
Secured Debt | Base Rate | Term Loan A and Revolving Facility
Debt Instrument [Line Items]
Debt basis spread on variable rate		1.00%
Secured Debt | LIBOR | Term Loan A and Revolving Facility
Debt Instrument [Line Items]
Debt basis spread on variable rate | Rate		2.50%
Secured Debt | LIBOR | Term Loan A and Revolving Facility | Minimum
Debt Instrument [Line Items]
Debt margin for base rate loans		1.25%
Secured Debt | LIBOR | Term Loan A and Revolving Facility | Maximum
Debt Instrument [Line Items]
Debt margin for base rate loans		2.75%
Secured Debt | LIBOR | Term Loan B Facility [Member]
Debt Instrument [Line Items]
Debt basis spread on variable rate | Rate		2.50%
Secured Debt | EURIBOR | Term Loan A and Revolving Facility | Minimum
Debt Instrument [Line Items]
Debt margin for base rate loans		0.25%
Secured Debt | EURIBOR | Term Loan A and Revolving Facility | Maximum
Debt Instrument [Line Items]
Debt margin for base rate loans		1.75%
5.125% Notes
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 1,200,000,000	$ 1,200,000,000
Debt Instrument, Interest Rate, Stated Percentage	5.125%	5.125%
Long-term debt	$ 1,200,000,000	$ 1,200,000,000		0
Revolving | Secured Debt
Debt Instrument [Line Items]
Secured revolving credit facility principal amount	1,300,000,000	1,300,000,000
Term loan facility
Debt Instrument [Line Items]
Total Term Loan Balance Outstanding	1,940,000,000	1,940,000,000
Long-term debt	1,910,000,000	1,910,000,000		733,000,000
Term loan facility | Secured Debt
Debt Instrument [Line Items]
Secured revolving credit facility principal amount	2,055,000,000.000	2,055,000,000.000
Revolving credit facility
Debt Instrument [Line Items]
Long-term debt	385,000,000	385,000,000		$ 75,000,000
Revolving Foreign | Secured Debt
Debt Instrument [Line Items]
Secured revolving credit facility principal amount	$ 400,000,000	$ 400,000,000