Revenue from Contracts with Customers - Contract Cost Balances (Details) - USD ($) |
12 Months Ended | ||
---|---|---|---|
Dec. 31, 2018 |
Jan. 01, 2018 |
Dec. 31, 2017 |
|
Capitalized Contract Cost [Line Items] | |||
Current contract cost assets | $ 30,000,000 | $ 62,000,000 | |
Non-current contract cost assets | 98,000,000 | $ 85,000,000 | $ 0 |
Contract cost, amortization | $ 44,000,000 | ||
Minimum | |||
Capitalized Contract Cost [Line Items] | |||
Capitalized contract cost, amortization period | 1 year | ||
Maximum | |||
Capitalized Contract Cost [Line Items] | |||
Capitalized contract cost, amortization period | 4 years |