Income Taxes - Schedule of the Deferred Tax Assets and Deferred Tax Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Accounts and notes receivable	$ 6	$ 4
Accrued employee benefits	54	48
Leases	114	99
Operating lease liabilities	323	332
Liabilities not currently deductible for tax	310	198
Tax loss and credit carryforwards	547	493
Derivatives	225	83
Other	9	3
Total gross deferred tax assets	1,588	1,260
Valuation allowance	(364)	(329)	$ (325)	$ (282)
Net deferred tax assets	1,224	931
Less deferred tax liabilities:
Property and equipment, principally due to differences in depreciation	35	40
Intangible assets	1,747	1,792
Leases	114	88
Operating lease assets	311	325
Statutory impairment	30	28
Outside basis difference	46	42
Total gross deferred tax liabilities	2,283	2,315
Net deferred tax liability	$ 1,059	$ 1,384