Debt - Term Loan Facility and Revolving Facility (Details)		3 Months Ended
	Feb. 06, 2017 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Line of Credit Facility [Line Items]
Line of credit facility, current borrowing capacity	$ 2,500,000,000
Debt instrument, number of maturity date extensions	1 year
Long-term line of credit		$ 9,741,618,000
Less deferred financing costs, net		(48,470,000)
Long-term debt		9,668,850,000
Revolving Facility
Line of Credit Facility [Line Items]
Line of credit facility, additional borrowing capacity	$ 1,500,000,000
Long-term line of credit		15,000,000
Less deferred financing costs, net		0
Long-term debt		$ 15,000,000
Debt covenant, net leverage ratio		8.00
Revolving Facility | Revolving Credit Facility
Line of Credit Facility [Line Items]
Line of credit facility, current borrowing capacity	1,000,000,000
Line of credit facility, interest rate at end of period		3.63%
Long-term line of credit		$ 15,000,000	$ 35,000,000
Revolving Facility | Term Loan Facility
Line of Credit Facility [Line Items]
Line of credit facility, current borrowing capacity	$ 1,500,000,000
Line of credit facility, interest rate at end of period		3.58%
Long-term line of credit		$ 1,500,000,000	1,500,000,000
Less deferred financing costs, net		(11,305,000)	(12,027,000)
Long-term debt		$ 1,488,695,000	$ 1,487,973,000
London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Debt instrument, variable rate		1.88%
London Interbank Offered Rate (LIBOR) | Revolving Facility
Line of Credit Facility [Line Items]
Basis spread		1.00%
London Interbank Offered Rate (LIBOR) | Revolving Facility | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread		1.75%
London Interbank Offered Rate (LIBOR) | Revolving Facility | Term Loan Facility
Line of Credit Facility [Line Items]
Basis spread		1.70%
Federal Funds Effective Swap Rate | Revolving Facility
Line of Credit Facility [Line Items]
Basis spread		0.50%
Minimum | Revolving Credit Facility
Line of Credit Facility [Line Items]
Line of credit facility, unused capacity, commitment fee percentage		0.35%
Line of credit facility, facility fee percentage		0.125%
Minimum | London Interbank Offered Rate (LIBOR) | Revolving Facility | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread		1.75%
Minimum | London Interbank Offered Rate (LIBOR) | Revolving Facility | Term Loan Facility
Line of Credit Facility [Line Items]
Basis spread		1.70%
Minimum | Base Rate | Revolving Facility | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread		0.75%
Minimum | Base Rate | Revolving Facility | Term Loan Facility
Line of Credit Facility [Line Items]
Basis spread		0.70%
Maximum | Revolving Credit Facility
Line of Credit Facility [Line Items]
Line of credit facility, unused capacity, commitment fee percentage		0.20%
Line of credit facility, facility fee percentage		0.30%
Maximum | London Interbank Offered Rate (LIBOR) | Revolving Facility | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread		2.30%
Maximum | London Interbank Offered Rate (LIBOR) | Revolving Facility | Term Loan Facility
Line of Credit Facility [Line Items]
Basis spread		2.30%
Maximum | Base Rate | Revolving Facility | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread		1.30%
Maximum | Base Rate | Revolving Facility | Term Loan Facility
Line of Credit Facility [Line Items]
Basis spread		1.30%