Debt (Details) - USD ($) |
Jun. 30, 2019 |
May 31, 2019 |
Apr. 30, 2019 |
Dec. 31, 2018 |
---|---|---|---|---|
Debt Instrument [Line Items] | ||||
Restricted cash | $ 86,000,000 | $ 88,000,000 | ||
Securitization Borrowings | ||||
Debt Instrument [Line Items] | ||||
Current borrowing capacity | $ 450,000,000 | $ 400,000,000 | ||
Accounts receivable securitization balance | 0 | $ 0 | ||
3.80% Senior Notes Due 2028 | Senior Notes | ||||
Debt Instrument [Line Items] | ||||
Debt instrument, face amount | $ 200,000,000 | |||
Interest rate, stated percentage | 3.80% | |||
4.10% Senior Notes Due 2049 | Senior Notes | ||||
Debt Instrument [Line Items] | ||||
Debt instrument, face amount | $ 400,000,000 | |||
Interest rate, stated percentage | 4.10% | |||
5.10% Senior Notes Due 2118 | Senior Notes | ||||
Debt Instrument [Line Items] | ||||
Debt instrument, face amount | $ 200,000,000 | |||
Interest rate, stated percentage | 5.10% |