Leases - Schedule Of Lease Expense For Finance And Operating Leases (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019
Finance lease expense:
Depreciation and amortization		$ 106	$ 93
Interest		31	32
Operating leases	[1]	447	389
Short-term lease expense	[1]	322	316
Variable lease expense	[1]	154	150
Total lease expense		$ 1,060	$ 980

[1] Expenses are included in “other operating expenses” in our consolidated income statements.