Fair Value of Financial Instruments - Schedule of Estimated Fair Value of Financial Instruments, by Balance Sheet Grouping (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Carrying Amount
Assets:
Cash and cash equivalents	$ 1,552	$ 216
Investments in equity securities	124	141
Available-for-sale debt securities	107	101
Trading securities	12	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	2,655	3,074
Carrying Amount | Senior Secured Notes | Senior Secured Notes at 8.625%, Due 2024
Liabilities:
Notes payable, fair value disclosure	1,024	1,023
Carrying Amount | Senior Secured Notes | Senior Secured Notes at 6.625% Due 2025
Liabilities:
Notes payable, fair value disclosure	1,423
Carrying Amount | Senior Secured Notes | Senior Secured Notes at 8%, Due 2026
Liabilities:
Notes payable, fair value disclosure	2,072	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	230	229
Carrying Amount | Senior Notes | Senior Notes at 6.875% Due 2028
Liabilities:
Notes payable, fair value disclosure	1,679	1,678
Carrying Amount | Junior-Priority Secured Notes | Junior-Priority Secured Notes at 9.875% Due 2023
Liabilities:
Notes payable, fair value disclosure	1,756	1,754
Carrying Amount | Junior-Priority Secured Notes | Junior-Priority Secured Notes at 8.125% Due 2024
Liabilities:
Notes payable, fair value disclosure	1,342	1,340
Carrying Amount | Receivables Facility and Other Debt, Type | ABL Facility and Other Debt
Liabilities:
Notes payable, fair value disclosure	23	285
Estimated Fair Value
Assets:
Cash and cash equivalents	1,552	216
Investments in equity securities	124	141
Available-for-sale debt securities	107	101
Trading securities	12	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	2,521	3,148
Estimated Fair Value | Senior Secured Notes | Senior Secured Notes at 8.625%, Due 2024
Liabilities:
Notes payable, fair value disclosure	1,012	1,099
Estimated Fair Value | Senior Secured Notes | Senior Secured Notes at 6.625% Due 2025
Liabilities:
Notes payable, fair value disclosure	1,388
Estimated Fair Value | Senior Secured Notes | Senior Secured Notes at 8%, Due 2026
Liabilities:
Notes payable, fair value disclosure	1,992	2,182
Estimated Fair Value | Senior Notes | Senior Notes at 6.875%, Due 2022
Liabilities:
Notes payable, fair value disclosure	190	188
Estimated Fair Value | Senior Notes | Senior Secured Notes at 8% Due 2027
Liabilities:
Notes payable, fair value disclosure	669	700
Estimated Fair Value | Senior Notes | Senior Notes at 6.875% Due 2028
Liabilities:
Notes payable, fair value disclosure	687	1,700
Estimated Fair Value | Junior-Priority Secured Notes | Junior-Priority Secured Notes at 9.875% Due 2023
Liabilities:
Notes payable, fair value disclosure	1,420	1,539
Estimated Fair Value | Junior-Priority Secured Notes | Junior-Priority Secured Notes at 8.125% Due 2024
Liabilities:
Notes payable, fair value disclosure	944	1,113
Estimated Fair Value | Receivables Facility and Other Debt, Type | ABL Facility and Other Debt
Liabilities:
Notes payable, fair value disclosure	$ 23	$ 285