Income Taxes (Schedule of Components of Deferred Income Taxes) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Assets
Net operating loss and credit carryforwards	$ 775	$ 743
Self-insurance liabilities	48	69
Long-term debt and interest	312	84
Accounts receivable	62	58
IRC Section 163(j) interest limitation	296	144
Accrued vacation	24	26
Accrued bonus	31
Other comprehensive income	5	4
Right-of-use-liability	149
Stock-based compensation	5	4
Deferred compensation	70	64
Other	51	15
Total	1,828	1,211
Valuation Allowance	(1,049)	(701)
Total Deferred Income Tax Assets, Net	779	510
Liabilities
Property and equipment	335	237
Prepaid expenses	30	27
Intangibles	149	134
Investments in unconsolidated affiliates	57	55
Other liabilities	9	14
IRC Section 481(a) - mixed service cost	216
Right-of-use-assets	145
Total Deferred Income Tax Liabilities, Gross	$ 941	$ 467