v3.19.2
Debt (First Lien Notes) (Details) - USD ($)
$ in Millions
Jun. 30, 2019
Dec. 31, 2018
Debt Instrument [Line Items]    
Long-term Debt $ 10,677 $ 10,156
2022 First Lien Notes [Member]    
Debt Instrument [Line Items]    
Long-term Debt 744 743
2024 First Lien Notes [Member]    
Debt Instrument [Line Items]    
Long-term Debt 487 486
2026 First Lien Notes [Member]    
Debt Instrument [Line Items]    
Long-term Debt 1,171 1,171
Corporate Debt Securities [Member]    
Debt Instrument [Line Items]    
Long-term Debt $ 2,402 $ 2,400