Condensed Consolidating Financial Information of Guarantor Subsidiaries - CONDENSED CONSOLIDATING CASH FLOW INFORMATION (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	$ 1,801	$ 1,551	$ 721
Net cash used in investing activities	(2,000)	(1,177)	(2,104)
Net cash provided by (used in) financing activities	196	(295)	1,453
Effect of foreign exchange rates	(14)	(10)	0
Net (decrease) increase in cash and cash equivalents	(17)	69	70
Cash and cash equivalents at beginning of year	175	106	36
Cash and cash equivalents at end of year	158	175	106
Eliminations
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	0	0	0
Net cash used in investing activities	0	0	0
Net cash provided by (used in) financing activities	0	0	0
Effect of foreign exchange rates	0	0	0
Net (decrease) increase in cash and cash equivalents	0	0	0
Cash and cash equivalents at beginning of year	0	0	0
Cash and cash equivalents at end of year	0	0	0
Parent
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	13	26	7
Net cash used in investing activities	(13)	(26)	(7)
Net cash provided by (used in) financing activities	0	0	0
Effect of foreign exchange rates	0	0	0
Net (decrease) increase in cash and cash equivalents	0	0	0
Cash and cash equivalents at beginning of year	0	0	0
Cash and cash equivalents at end of year	0	0	0
URNA
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	1,644	1,285	654
Net cash used in investing activities	(1,773)	(1,018)	(1,851)
Net cash provided by (used in) financing activities	120	(270)	1,211
Effect of foreign exchange rates	0	0	0
Net (decrease) increase in cash and cash equivalents	(9)	(3)	14
Cash and cash equivalents at beginning of year	17	20	6
Cash and cash equivalents at end of year	8	17	20
Guarantor Subsidiaries
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	4	4	151
Net cash used in investing activities	0	0	(155)
Net cash provided by (used in) financing activities	(4)	(4)	4
Effect of foreign exchange rates	0	0	0
Net (decrease) increase in cash and cash equivalents	0	0	0
Cash and cash equivalents at beginning of year	0	0	0
Cash and cash equivalents at end of year	0	0	0
Non Guarantor Subsidiaries - Foreign
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	223	216	153
Net cash used in investing activities	(214)	(133)	(91)
Net cash provided by (used in) financing activities	(3)	(1)	(6)
Effect of foreign exchange rates	(14)	(10)	0
Net (decrease) increase in cash and cash equivalents	(8)	72	56
Cash and cash equivalents at beginning of year	158	86	30
Cash and cash equivalents at end of year	150	158	86
Non Guarantor Subsidiaries - SPV
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	(83)	20	(244)
Net cash used in investing activities	0	0	0
Net cash provided by (used in) financing activities	83	(20)	244
Effect of foreign exchange rates	0	0	0
Net (decrease) increase in cash and cash equivalents	0	0	0
Cash and cash equivalents at beginning of year	0	0	0
Cash and cash equivalents at end of year	$ 0	$ 0	$ 0

Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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Amount of increase (decrease) in cash and cash equivalents. Cash and cash equivalents are the amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Includes effect from exchange rate changes.

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Amount of increase (decrease) from the effect of exchange rate changes on cash and cash equivalent balances held in foreign currencies.

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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.

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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.

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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.

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