Guarantor Condensed Consolidating Financial Information - Impact of revision on Condensed Consolidating Statements of Cash Flows (Details 1) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Financial Statements, Captions [Line Items]
Cash provided by operating activities	$ 182	$ 505	$ 798
Cash used for investing activities	(497)	(560)	(424)
Cash provided by (used for) financing activities	687	55	(374)
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Cash provided by operating activities	(119)	0	0
Cash used for investing activities	0	0	0
Cash provided by (used for) financing activities	119	0	0
Parent Company [Member] \| Scenario, Previously Reported [Member]
Condensed Financial Statements, Captions [Line Items]
Cash provided by operating activities	(119)
Cash used for investing activities	0
Cash provided by (used for) financing activities	119
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Cash provided by operating activities	171	302	388
Cash used for investing activities	(446)	(237)	(192)
Cash provided by (used for) financing activities	370	(65)	(196)
Guarantor Subsidiaries [Member] \| Scenario, Previously Reported [Member]
Condensed Financial Statements, Captions [Line Items]
Cash provided by operating activities	(125)
Cash used for investing activities	(446)
Cash provided by (used for) financing activities	666
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Cash provided by operating activities	121	208	409
Cash used for investing activities	(253)	(323)	(232)
Cash provided by (used for) financing activities	409	115	(177)
Non-Guarantor Subsidiaries [Member] \| Scenario, Previously Reported [Member]
Condensed Financial Statements, Captions [Line Items]
Cash provided by operating activities	440
Cash used for investing activities	(253)
Cash provided by (used for) financing activities	90
Consolidation, Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Cash provided by operating activities	9	9	1
Cash used for investing activities	202	0	0
Cash provided by (used for) financing activities	(211)	$ 5	$ (1)
Consolidation, Eliminations [Member] \| Scenario, Previously Reported [Member]
Condensed Financial Statements, Captions [Line Items]
Cash provided by operating activities	(14)
Cash used for investing activities	202
Cash provided by (used for) financing activities	$ (188)

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

+ Details

Name:	us-gaap_CondensedFinancialStatementsCaptionsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of cash inflow (outflow) from financing activities, including discontinued operations. Financing activity cash flows include obtaining resources from owners and providing them with a return on, and a return of, their investment; borrowing money and repaying amounts borrowed, or settling the obligation; and obtaining and paying for other resources obtained from creditors on long-term credit.

+ References

+ Details

Name:	us-gaap_NetCashProvidedByUsedInFinancingActivities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of cash inflow (outflow) from investing activities, including discontinued operations. Investing activity cash flows include making and collecting loans and acquiring and disposing of debt or equity instruments and property, plant, and equipment and other productive assets.

+ References

+ Details

Name:	us-gaap_NetCashProvidedByUsedInInvestingActivities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of cash inflow (outflow) from operating activities, including discontinued operations. Operating activity cash flows include transactions, adjustments, and changes in value not defined as investing or financing activities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 24
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3521-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3536-108585

+ Details

Name:	us-gaap_NetCashProvidedByUsedInOperatingActivities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	dei_LegalEntityAxis=us-gaap_ParentCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementScenarioAxis=us-gaap_ScenarioPreviouslyReportedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=us-gaap_GuarantorSubsidiariesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=us-gaap_NonGuarantorSubsidiariesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConsolidationItemsAxis=us-gaap_ConsolidationEliminationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: