v3.19.1

Debt (Textuals) (Details) - USD ($) $ in Millions | 3 Months Ended | 12 Months Ended |  |
--- | --- | --- | --- | ---
Jun. 30, 2018 | Jun. 30, 2016 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | Apr. 11, 2018 | Mar. 31, 2018
Debt Instrument [Line Items] |  |  |  |  |  |  |
Maximum Remaining Lease Term |  |  | 33 years |  |  |  |
Lease Assets, Historical Cost |  |  | $ 715 | $ 737 |  |  |
Lease Assets, Accumulated Depreciation |  |  | 353 | 349 |  |  |
Gains (Losses) on Extinguishment of Debt |  |  | $ 28 | (38) | $ (25) |  |
Revolving Credit Facility [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Repayment time for drawings under letters of credit |  |  | 2 days |  |  |  |
Revolving Credit Facility [Member] | Minimum [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Applicable margin range percentage above base rate |  |  | 1.00% |  |  |  |
Applicable Margin Range Percentage Above British Bankers' Association Interest Settlement Rates |  |  | 2.00% |  |  |  |
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage |  |  | 0.25% |  |  |  |
Revolving Credit Facility [Member] | Maximum [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Applicable margin range percentage above base rate |  |  | 1.25% |  |  |  |
Applicable Margin Range Percentage Above British Bankers' Association Interest Settlement Rates |  |  | 2.25% |  |  |  |
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage |  |  | 0.50% |  |  |  |
New 2023 First Lien Term Loan [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt Instrument, Face Amount |  | $ 562 |  |  |  |  |
CDHI [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Letter of Credit Total |  |  | $ 300 |  |  |  |
2026 First Lien Notes [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt Instrument, Face Amount |  | $ 625 |  | 560 |  |  |
One Month [Member] | Revolving Credit Facility [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Interest periods for LIBOR rate borrowings |  |  | 1 month |  |  |  |
Two Months [Member] | Revolving Credit Facility [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Interest periods for LIBOR rate borrowings |  |  | 2 months |  |  |  |
Three Months [Member] | Revolving Credit Facility [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Interest periods for LIBOR rate borrowings |  |  | 3 months |  |  |  |
Six Months [Member] | Revolving Credit Facility [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Interest periods for LIBOR rate borrowings |  |  | 6 months |  |  |  |
Nine Months [Member] | Revolving Credit Facility [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Interest periods for LIBOR rate borrowings |  |  | 9 months |  |  |  |
Twelve Months [Member] | Revolving Credit Facility [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Interest periods for LIBOR rate borrowings |  |  | 12 months |  |  |  |
Prime Rate Or The Eurodollar Rate For a One Month Interest Period [Member] | New 2023 First Lien Term Loan [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate |  | 2.00% |  |  |  |  |
Federal Funds Effective Rate [Member] | Revolving Credit Facility [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate |  |  | 0.50% |  |  |  |
Federal Funds Effective Rate [Member] | New 2023 First Lien Term Loan [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate |  | 0.50% |  |  |  |  |
Eurodollar Rate For A One-Month Interest Period [Member] | New 2023 First Lien Term Loan [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate |  | 1.00% |  |  |  |  |
CDHI [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Future Line of Credit Facility Maximum Borrowing Capacity |  |  | $ 125 |  |  |  |
Other Corporate Facilities [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Line of Credit Facility, Maximum Borrowing Capacity |  |  | 200 |  |  |  |
Other Corporate Facilities [Member] | Goldman Sachs [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Line of Credit Facility, Maximum Borrowing Capacity |  |  | 150 |  |  |  |
Other Corporate Facilities [Member] | Citi Bank [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Line of Credit Facility, Maximum Borrowing Capacity |  |  | $ 50 |  |  |  |
Short Term Credit Facility [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Line of Credit Facility, Maximum Borrowing Capacity |  |  |  |  |  | $ 300 |
Amendment No. 8 [Member] | Revolving Credit Facility [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Line of Credit Facility, Increase (Decrease), Net | $ 220 |  |  |  |  |  |
Revolving Credit Facility [Member] | Amendment No. 7 [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Total Letter of Credit Sublimit |  |  |  |  |  |  | $ 1,300
Incremental Revolving Facilities |  |  |  |  |  |  | 500
Revolving Credit Facility [Member] | Amendment No. 8 [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Line of Credit Facility, Maximum Borrowing Capacity | 1,690 |  |  |  |  |  |
Revolving Credit Facility [Member] | Amendment No. 6 [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Line of Credit Facility, Maximum Borrowing Capacity | $ 1,470 |  |  |  |  |  |
Total Letter of Credit Sublimit |  |  |  |  |  |  | $ 1,150
Future Line of Credit Facility Maximum Borrowing Capacity |  |  |  | $ 1,300 |  |  |

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