Leases Components of balance sheet (Details) - USD ($) $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
|---|---|---|
| Operating lease right-of-use assets (non-current) | $ 931 | $ 0 |
| Current portion of operating lease liabliities | 208 | 0 |
| Operating lease liabilities (non-current) | 825 | $ 0 |
| Other assets | ||
| Finance leases - Other assets (non-current) | 123 | |
| Other current liabilities | ||
| Finance leases - Other current liabilities | 19 | |
| Other liabilities | ||
| Finance leases - Other liabilities (non-current) | $ 124 |