Borrowings - Interest on Debt (Details) - USD ($) $ in Millions |
3 Months Ended | |
|---|---|---|
Mar. 31, 2018 |
Mar. 31, 2017 |
|
| Interest on Debt | ||
| Interest capitalized | $ 3 | $ 0 |
| Total interest paid and accrued | 349 | 293 |
| Cost of Financing | ||
| Interest on Debt | ||
| Interest paid | 182 | 158 |
| Interest Expense | ||
| Interest on Debt | ||
| Interest paid | $ 165 | $ 135 |