Long-Term Debt - Summary of Long-Term Debt (Details) - USD ($) $ in Millions	9 Months Ended
Sep. 30, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Debt, gross	$ 8,864	$ 8,539
Unamortized premium (discount) and debt issue cost, net	17	(99)
Total debt	8,881	8,440
Less: current maturities	(1,080)	(2,145)
Total long-term debt	7,801	6,295
Pacific Term Loan B-1 \| Term Loan
Debt Instrument [Line Items]
Debt, gross	0	1,048
Pacific Revolving Credit Facility \| Revolving Credit Facility
Debt Instrument [Line Items]
Debt, gross	0	0
2015 Term Loan Facility \| Term Loan
Debt Instrument [Line Items]
Debt, gross	0	490
2015 Revolving Credit Facility \| Revolving Credit Facility
Debt Instrument [Line Items]
Debt, gross	$ 0	0
Certificates \| Secured Debt
Debt Instrument [Line Items]
Maturity dates range, start	Jan. 01, 2018
Maturity dates range, end	Dec. 31, 2027
Debt, gross	$ 2,010	2,380
Certificates \| Secured Debt \| Minimum
Debt Instrument [Line Items]
Interest rate per annum (percent)	3.63%
Certificates \| Secured Debt \| Maximum
Debt Instrument [Line Items]
Interest rate per annum (percent)	8.02%
Notes \| Secured Debt
Debt Instrument [Line Items]
Maturity dates range, start	Jan. 01, 2018
Maturity dates range, end	Dec. 31, 2026
Debt, gross	$ 1,281	1,961
Notes \| Secured Debt \| Minimum
Debt Instrument [Line Items]
Interest rate per annum (percent)	2.75%
Notes \| Secured Debt \| Maximum
Debt Instrument [Line Items]
Interest rate per annum (percent)	6.54%
2018 Unsecured Notes \| Unsecured Debt
Debt Instrument [Line Items]
Maturity dates range, start	Jan. 01, 2021
Maturity dates range, end	Dec. 31, 2028
Debt, gross	$ 1,600	0
2018 Unsecured Notes \| Unsecured Debt \| Minimum
Debt Instrument [Line Items]
Interest rate per annum (percent)	3.40%
2018 Unsecured Notes \| Unsecured Debt \| Maximum
Debt Instrument [Line Items]
Interest rate per annum (percent)	4.38%
2018 Unsecured Revolving Credit Facility \| Unsecured Debt
Debt Instrument [Line Items]
Maturity dates range, start	Jan. 01, 2021
Maturity dates range, end	Dec. 31, 2023
Debt, gross	$ 0	0
NYTDC Special Facilities Revenue Bonds, Series 2018 \| Bonds
Debt Instrument [Line Items]
Maturity dates range, start	Jan. 01, 2022
Maturity dates range, end	Dec. 31, 2036
Debt, gross	$ 1,383	0
NYTDC Special Facilities Revenue Bonds, Series 2018 \| Bonds \| Minimum
Debt Instrument [Line Items]
Interest rate per annum (percent)	4.00%
NYTDC Special Facilities Revenue Bonds, Series 2018 \| Bonds \| Maximum
Debt Instrument [Line Items]
Interest rate per annum (percent)	5.00%
Other unsecured notes \| Unsecured Debt
Debt Instrument [Line Items]
Maturity dates range, start	Jan. 01, 2020
Maturity dates range, end	Dec. 31, 2022
Debt, gross	$ 2,450	2,450
Other unsecured notes \| Unsecured Debt \| Minimum
Debt Instrument [Line Items]
Interest rate per annum (percent)	2.60%
Other unsecured notes \| Unsecured Debt \| Maximum
Debt Instrument [Line Items]
Interest rate per annum (percent)	3.63%
Other financings \| Secured and Unsecured Debt
Debt Instrument [Line Items]
Maturity dates range, start	Jan. 01, 2019
Maturity dates range, end	Dec. 31, 2030
Debt, gross	$ 140	210
Other financings \| Secured and Unsecured Debt \| Minimum
Debt Instrument [Line Items]
Interest rate per annum (percent)	1.81%
Other financings \| Secured and Unsecured Debt \| Maximum
Debt Instrument [Line Items]
Interest rate per annum (percent)	8.75%
Other revolving credit facilities \| Revolving Credit Facility
Debt Instrument [Line Items]
Maturity dates range, start	Jan. 01, 2019
Maturity dates range, end	Dec. 31, 2021
Debt, gross	$ 0	$ 0
Available borrowing capacity	$ 537

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Amount of unamortized debt discount (premium) and debt issuance costs.

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Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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