Long-Term Debt and Revolving Promissory Note (Tables)

12 Months Ended

Dec. 31, 2017

Debt Disclosure [Abstract]

Schedule of long-term debt, including unamortized discounts and premiums

Long-term debt, including unamortized premiums and discounts, unamortized debt issuance costs and note payable-affiliate, were as follows:

			As of December 31,
	Interest Rates	Maturities	2017			2016
			(Dollars in millions)
Senior notes	6.125% - 7.750%	2021 - 2057	$	7,294		7,259
Term loan	3.570%	2025	100			100
Capital lease and other obligations	Various	Various	36			32
Unamortized premiums, net			1			4
Unamortized debt issuance costs			(150		)	(134	)
Total long-term debt			7,281			7,261
Less current maturities			(17		)	(514	)
Long-term debt, excluding current maturities			$	7,264		6,747
Note payable-affiliate	6.710%	2022	$	965		914

Schedule of aggregate maturities of the entity's long-term debt (excluding unamortized premiums, discounts, and other)

Set forth below is the aggregate principal amount of our long-term debt (excluding unamortized premiums and discounts and unamortized debt issuance costs and other and excluding note payable-affiliate) maturing during the following years:

	(Dollars in millions)(1)
2018	$	17
2019	10
2020	5
2021	951
2022	1
2023 and thereafter	6,446
Total long-term debt	$	7,430

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⁽¹⁾ Actual principal paid in any year may differ due to the possible future refinancing of outstanding debt or the issuance of new debt.

Schedule of amount of gross interest expense, net of capitalized interest and interest expense (income)-affiliates

Interest expense includes interest on total long-term debt. The following table presents the amount of gross interest expense, net of capitalized interest and interest expense-affiliates, net:

	Years Ended December 31,
	2017			2016		2015
	(Dollars in millions)
Interest expense:
Gross interest expense	$	497		497		491
Capitalized interest	(32		)	(19	)	(18	)
Total interest expense	$	465		478		473
Interest expense-affiliates, net	$	63		59		53