Fair Value of Financial Instruments - Schedule of Estimated Fair Value of Financial Instruments, by Balance Sheet Grouping (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Carrying Amount
Assets:
Cash and cash equivalents	$ 1,823	$ 216
Investments in equity securities	124	141
Available-for-sale debt securities	105	101
Trading securities	13	12
Carrying Amount | Senior Secured Notes | Senior Secured Notes at 5.125%, Due 2021
Liabilities:
Notes payable, fair value disclosure		990
Carrying Amount | Senior Secured Notes | Senior Secured Notes at 6.25%, Due 2023
Liabilities:
Notes payable, fair value disclosure	2,657	3,074
Carrying Amount | Senior Secured Notes | Senior Secured Notes at 8.625%, Due 2024
Liabilities:
Notes payable, fair value disclosure	1,025	1,023
Carrying Amount | Senior Secured Notes | Senior Secured Notes at 6.625% Due 2025
Liabilities:
Notes payable, fair value disclosure	1,425
Carrying Amount | Senior Secured Notes | Senior Secured Notes at 8%, Due 2026
Liabilities:
Notes payable, fair value disclosure	2,073	2,070
Carrying Amount | Senior Secured Notes | Senior Secured Notes at 8% Due 2027
Liabilities:
Notes payable, fair value disclosure	691	691
Carrying Amount | Senior Notes | Senior Notes at 6.875%, Due 2022
Liabilities:
Notes payable, fair value disclosure	196	229
Carrying Amount | Senior Notes | Senior Notes at 6.875% Due 2028
Liabilities:
Notes payable, fair value disclosure	1,456	1,678
Carrying Amount | Junior-Priority Secured Notes | Junior-Priority Secured Notes at 9.875% Due 2023
Liabilities:
Notes payable, fair value disclosure	1,757	1,754
Carrying Amount | Junior-Priority Secured Notes | Junior-Priority Secured Notes at 8.125% Due 2024
Liabilities:
Notes payable, fair value disclosure	1,341	1,340
Carrying Amount | Receivables Facility and Other Debt, Type | ABL Facility and Other Debt
Liabilities:
Notes payable, fair value disclosure	17	285
Estimated Fair Value
Assets:
Cash and cash equivalents	1,823	216
Investments in equity securities	124	141
Available-for-sale debt securities	105	101
Trading securities	13	12
Estimated Fair Value | Senior Secured Notes | Senior Secured Notes at 5.125%, Due 2021
Liabilities:
Notes payable, fair value disclosure		1,003
Estimated Fair Value | Senior Secured Notes | Senior Secured Notes at 6.25%, Due 2023
Liabilities:
Notes payable, fair value disclosure	2,617	3,148
Estimated Fair Value | Senior Secured Notes | Senior Secured Notes at 8.625%, Due 2024
Liabilities:
Notes payable, fair value disclosure	1,028	1,099
Estimated Fair Value | Senior Secured Notes | Senior Secured Notes at 6.625% Due 2025
Liabilities:
Notes payable, fair value disclosure	1,417
Estimated Fair Value | Senior Secured Notes | Senior Secured Notes at 8%, Due 2026
Liabilities:
Notes payable, fair value disclosure	2,070	2,182
Estimated Fair Value | Senior Notes | Senior Notes at 6.875%, Due 2022
Liabilities:
Notes payable, fair value disclosure	176	188
Estimated Fair Value | Senior Notes | Senior Secured Notes at 8% Due 2027
Liabilities:
Notes payable, fair value disclosure	685	700
Estimated Fair Value | Senior Notes | Senior Notes at 6.875% Due 2028
Liabilities:
Notes payable, fair value disclosure	697	1,700
Estimated Fair Value | Junior-Priority Secured Notes | Junior-Priority Secured Notes at 9.875% Due 2023
Liabilities:
Notes payable, fair value disclosure	1,402	1,539
Estimated Fair Value | Junior-Priority Secured Notes | Junior-Priority Secured Notes at 8.125% Due 2024
Liabilities:
Notes payable, fair value disclosure	990	1,113
Estimated Fair Value | Receivables Facility and Other Debt, Type | ABL Facility and Other Debt
Liabilities:
Notes payable, fair value disclosure	$ 17	$ 285