Borrowings - Interest on Debt (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Interest on Debt
Interest capitalized	$ 3	$ 6
Total interest paid and accrued	1,167	1,323
Cost of financing
Interest on Debt
Interest paid	312	346
Interest expense
Interest on Debt
Interest paid	$ 852	$ 971