Debt and Credit Facility - Credit Facility (Details) - USD ($)	1 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	May 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Mar. 31, 2019	Jun. 30, 2019
Line of Credit Facility [Line Items]
Debt issuance amortization			$ 70,900,000		$ 83,600,000
Revolving Credit Facility
Line of Credit Facility [Line Items]
Proceeds from borrowings on revolving loan under credit facility			682,000,000.0	$ 3,725,500,000
Term Loan Facility
Line of Credit Facility [Line Items]
Proceeds from borrowings on revolving loan under credit facility			0	$ 3,000,000,000.0
Line of Credit
Line of Credit Facility [Line Items]
Debt issuance amortization	$ 1,750,000
Line of Credit | Revolving Credit Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity	3,570,000,000					$ 3,600,000,000
Debt issuance amortization			$ 13,600,000		14,700,000
Extinguishment of debt, amount					244,300,000
Restrictive covenants, maximum replacement financing	$ 2,000,000,000.0
Restrictive covenants, maximum replacement financing, term	3 years
Restrictive covenants, maximum transfer or assignment of securitization assets	$ 600,000,000
Interest coverage ratio, less than			3.25
Interest rate spread on overdue principal in event of default			2.00%
Interest rate spread on overdue amounts in event of default			2.00%
Line of Credit | Revolving Credit Facility | Leverage Ratio Percent One
Line of Credit Facility [Line Items]
Line of credit facility, covenant, total leverage ratio, maximum			6.75
Line of credit facility covenant, total indebtedness, convertible debt excluded, maximum			$ 700,000,000
Total leverage ratio, temporary maximum allowed, next three quarters			4.75
Line of Credit | Revolving Credit Facility | Leverage Ratio Percent Two
Line of Credit Facility [Line Items]
Line of credit facility, covenant, total leverage ratio, maximum			6.25
Total leverage ratio, temporary maximum allowed, next three quarters			4.25
Line of Credit | Revolving Credit Facility | Leverage Ratio Percent Three
Line of Credit Facility [Line Items]
Line of credit facility, covenant, total leverage ratio, maximum			5.75
Total leverage ratio, temporary maximum allowed, next three quarters			3.75
Line of Credit | Revolving Credit Facility | Minimum | Base Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.00%		0.00%
Line of Credit | Revolving Credit Facility | Minimum | London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.00%		1.00%
Line of Credit | Revolving Credit Facility | Maximum | Base Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.75%		0.75%
Line of Credit | Revolving Credit Facility | Maximum | London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.75%		1.75%
Line of Credit | Revolving Credit Facility | 2023 Tranche
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 3,570,000,000
Line of Credit | Foreign Line of Credit
Line of Credit Facility [Line Items]
Maximum borrowing capacity			$ 250,000,000.0
Line of Credit | Standby Letters of Credit
Line of Credit Facility [Line Items]
Maximum borrowing capacity			50,000,000.0
Line of Credit | Line of Credit Facility Swingline Loan Sublimit
Line of Credit Facility [Line Items]
Maximum borrowing capacity			25,000,000.0
Line of Credit | Term Loan Facility
Line of Credit Facility [Line Items]
Debt issuance amortization		$ 34,700,000	$ 15,300,000		19,400,000
Proceeds from borrowings on term loan facility		$ 3,000,000,000.0
Quarterly amortization payments, percent			0.25%
Repayments of long-term debt			$ 188,000,000.0		1,090,000,000.00
Loss on settlement of debt			$ 1,900,000		11,500,000
Proceeds from borrowings on revolving loan under credit facility					$ 500,000,000.0
Line of Credit | Term Loan Facility | Leverage Ratio Percent One
Line of Credit Facility [Line Items]
Mandatory prepayment of excess cash flow, percentage			50.00%
Line of Credit | Term Loan Facility | Leverage Ratio Percent Two
Line of Credit Facility [Line Items]
Mandatory prepayment of excess cash flow, percentage			25.00%
Line of Credit | Term Loan Facility | Leverage Ratio Percent Three
Line of Credit Facility [Line Items]
Mandatory prepayment of excess cash flow, percentage			0.00%