Subsequent Event - Chapter 11 Bankruptcy (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Subsequent Event [Line Items]
Due Within One Year	$ 3,875	$ 3,716
ABL Facility [Domain]
Subsequent Event [Line Items]
Line of Credit, Current	296
Due Within One Year	296	137
9.2% Debentures Due 2021 [Member]
Subsequent Event [Line Items]
Due Within One Year	74	74
7.875% Debentures Due 2023 [Member]
Subsequent Event [Line Items]
Due Within One Year	189	189
9.00% Second-Priority Senior Secured Notes Due 2020 [Member]
Subsequent Event [Line Items]
Due Within One Year	574	574
6.625% First Priority Senior Notes Due 2020 [Member]
Subsequent Event [Line Items]
Due Within One Year	1,550	1,550
10.00% First Priority Senior Notes Due 2020 [Member]
Subsequent Event [Line Items]
Due Within One Year	315	315
10.375% First-Priority Senion Secured Notes due 2022 [Member]
Subsequent Event [Line Items]
Due Within One Year	560	560
13.75% Senior Secured Notes due 2022 [Member]
Subsequent Event [Line Items]
Due Within One Year	$ 225	$ 225

The carrying value as of the balance sheet date of the current portion of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(13))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_LinesOfCreditCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant