Borrowings - Interest on Debt (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Interest on Debt
Interest capitalized	$ 5	$ 3
Total interest paid and accrued	1,478	1,101
Cost of financing
Interest on Debt
Interest paid	483	568
Interest expense
Interest on Debt
Interest paid	$ 990	$ 530