Debt Obligations - Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument
Junior Subordinated Notes	$ 54	$ 54
Note payable to related party	356	113
Other Long-term Debt	0	5
Unamortized Net Premiums And Fair Value Adjustments	16	28
Total debt outstanding	401	818
Less: Current maturities of long-term debt	152	407
Long-term Debt, Excluding Current Maturities	249	411
Senior Notes due 2018 [Member]
Debt Instrument
Senior Notes	$ 0	400
Debt Instrument, Interest Rate, Stated Percentage	7.00%
8.125% Senior Notes due 2019
Debt Instrument
Senior Notes	$ 150	150
Debt Instrument, Interest Rate, Stated Percentage	8.125%
7.60% Senior Notes, due February 1, 2024 [Member]
Debt Instrument
Senior Notes	$ 82	82
Debt Instrument, Interest Rate, Stated Percentage	7.60%
Senior Notes Due 2029 [Member]
Debt Instrument
Senior Notes	$ 66	66
Debt Instrument, Interest Rate, Stated Percentage	7.00%
8.25% Senior Notes, due November 14, 2029 [Member]
Debt Instrument
Senior Notes	$ 33	$ 33
Debt Instrument, Interest Rate, Stated Percentage	8.25%
Panhandle [Member]
Debt Instrument
Junior Subordinated Notes	$ 600

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Including the current and noncurrent portions, carrying value as of the balance sheet date of long-term debt (with maturities initially due after one year or beyond the operating cycle if longer) identified as Junior Subordinated Notes, which have a lower priority than senior instruments.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion. Senior note holders are paid off in full before any payments are made to junior note holders.

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