v3.19.1
Debt (First Lien Term Loans) (Details) - USD ($)
$ in Millions
Mar. 31, 2019
Dec. 31, 2018
Debt Instrument [Line Items]    
Long-term Debt $ 10,682 $ 10,156
New 2019 First Lien Term Loan [Member]    
Debt Instrument [Line Items]    
Long-term Debt 389 389
2023 First Lien Term Loan [Member]    
Debt Instrument [Line Items]    
Long-term Debt 1,057 1,059
2024 First Lien Term Loan [Member]    
Debt Instrument [Line Items]    
Long-term Debt 1,526 1,528
First Lien Term Loans [Member]    
Debt Instrument [Line Items]    
Long-term Debt $ 2,972 $ 2,976