Leases, Remaining Minimum Lease Payments (Details) - USD ($) $ in Millions		Mar. 31, 2020	Dec. 31, 2019
Operating Leases
2020	[1]	$ 302
2020			$ 376
2021		273	250
2022		205	194
2023		170	160
2024		133	125
Thereafter		489	498
Total undiscounted lease payments		1,572	1,603
Less: Amount associated with discounting		302	313
Total lease liabilities		1,270	1,290
Finance Leases
2020	[1]	123
2020			88
2021		164	86
2022		165	87
2023		171	91
2024		162	82
Thereafter		2,895	1,011
Total undiscounted lease payments		3,680	1,445
Less: Amount associated with discounting		1,468	654
Total lease liabilities		$ 2,212	$ 791

[1] The amounts as of March 31, 2020 are for the remaining nine months of 2020.