Debt (Schedule of long-term debt instruments) (Details) - USD ($)		1 Months Ended		6 Months Ended		12 Months Ended
		Apr. 30, 2015	Mar. 31, 2015	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2023	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2018	Dec. 31, 2014	Apr. 30, 2014	Nov. 30, 2009
Debt Instrument
Total debt				$ 8,410,000,000						$ 8,052,000,000
Less short-term portion	[1]			(590,000,000)						(618,000,000)
Total long-term debt				7,820,000,000						7,434,000,000
Loss on repurchase/redemption of debt securities and amendment of ABL facility				$ 123,000,000	$ 75,000,000
Accounts Receivable Securitization Facility
Debt Instrument
Credit facility interest rate at period end				0.90%
5 3/4 percent Senior Secured Notes
Debt Instrument
Stated interest rate				5.75%
8 3/8 percent Senior Subordinated Notes
Debt Instrument
Stated interest rate				8.375%
7 3/8 percent Senior Notes
Debt Instrument
Stated interest rate				7.375%
8 1/4 percent Senior Notes
Debt Instrument
Stated interest rate				8.25%
Redemption notice, amount		$ 350,000,000
7 5/8 percent Senior Notes
Debt Instrument
Stated interest rate				7.625%
6 1/8 percent Senior Notes
Debt Instrument
Stated interest rate				6.125%
4 5/8 percent Senior Notes
Debt Instrument
Stated interest rate				4.625%
5 3/4 percent Senior Notes
Debt Instrument
Stated interest rate				5.75%
5 1/2 percent Senior Notes
Debt Instrument
Stated interest rate				5.50%
Credit facility | $2.5 billion ABL Facility
Debt Instrument
Current borrowing capacity under credit facility				$ 680,000,000
Credit facility interest rate at period end				1.80%
Letters of credit outstanding				$ 49,000,000
Average outstanding amount				$ 1,200,000,000
Weighted average interest rate, long-term				2.00%
ABL Facility maximum month-end outstanding amount				$ 1,800,000,000
Senior secured notes | 4 5/8 percent Senior Notes
Debt Instrument
Face amount			$ 1,000,000,000
Proceeds from issuance of long-term debt			$ 990,000,000
Redemption price, percentage			101.00%
Senior notes | 5 3/4 percent Senior Notes
Debt Instrument
Face amount											$ 850,000,000
Senior notes | 5 1/2 percent Senior Notes
Debt Instrument
Face amount			$ 800,000,000
Proceeds from issuance of long-term debt			$ 792,000,000
Redemption price, percentage			101.00%
Accounts receivable facility | Accounts Receivable Securitization Facility
Debt Instrument
Current borrowing capacity under credit facility				1,000,000
Average outstanding amount under facility				$ 456,000,000
Weighted average interest rate, short-term				0.80%
A/R Securitization maximum month-end outstanding amount				$ 550,000,000
Collateral amount				627,000,000
Convertible senior notes | Convertible subordinated notes—4 percent
Debt Instrument
Total debt	[2]			$ 7,000,000						32,000,000
Stated interest rate				4.00%	4.00%
Loss on repurchase/redemption of debt securities and amendment of ABL facility				$ 1,000,000
Face amount				8,000,000								$ 173,000,000
Unamortized discount				1,000,000
Extinguishment of debt, amount				$ 26,000,000
Convertible, conversion price (in dollars per share)				$ 11.11
URNA and subsidiaries
Debt Instrument
Total debt				$ 8,403,000,000						8,020,000,000
URNA and subsidiaries | $2.5 billion ABL Facility
Debt Instrument
Maximum borrowing capacity			$ 2,500,000,000.0	2,500,000,000.0
URNA and subsidiaries | Capital leases
Debt Instrument
Total debt				92,000,000						105,000,000
URNA and subsidiaries | Credit facility | $2.5 billion ABL Facility
Debt Instrument
Total debt	[3]			1,771,000,000						1,304,000,000
URNA and subsidiaries | Senior secured notes | 5 3/4 percent Senior Secured Notes
Debt Instrument
Total debt	[4]			0						750,000,000
URNA and subsidiaries | Senior secured notes | 4 5/8 percent Senior Notes
Debt Instrument
Total debt	[5]			1,000,000,000						0
URNA and subsidiaries | Senior notes | 7 3/8 percent Senior Notes
Debt Instrument
Total debt				750,000,000						750,000,000
URNA and subsidiaries | Senior notes | 8 1/4 percent Senior Notes
Debt Instrument
Total debt	[6]			316,000,000						687,000,000
URNA and subsidiaries | Senior notes | 7 5/8 percent Senior Notes
Debt Instrument
Total debt				1,325,000,000						1,325,000,000
URNA and subsidiaries | Senior notes | 6 1/8 percent Senior Notes
Debt Instrument
Total debt				950,000,000						951,000,000
URNA and subsidiaries | Senior notes | 5 3/4 percent Senior Notes
Debt Instrument
Total debt				850,000,000						850,000,000
URNA and subsidiaries | Senior notes | 5 1/2 percent Senior Notes
Debt Instrument
Total debt	[7]			800,000,000						0
URNA and subsidiaries | Senior subordinated notes | 8 3/8 percent Senior Subordinated Notes
Debt Instrument
Total debt	[4]			0						750,000,000
URNA and subsidiaries | Accounts receivable facility | Accounts Receivable Securitization Facility
Debt Instrument
Total debt	[8]			$ 549,000,000						$ 548,000,000
Forecast | Senior secured notes | 4 5/8 percent Senior Notes
Debt Instrument
Redemption price, percentage							100.00%		103.469%
Forecast | Senior notes | 5 1/2 percent Senior Notes
Debt Instrument
Redemption price, percentage						100.00%		102.75%
Interest expense, net | 5 3/4 percent Senior Secured Notes and 8 3/8 percent Senior Subordinated Notes
Debt Instrument
Loss on repurchase/redemption of debt securities and amendment of ABL facility		106,000,000
Interest expense, net | 8 1/4 percent Senior Notes
Debt Instrument
Loss on repurchase/redemption of debt securities and amendment of ABL facility		$ 15,000,000

[1] As of June 30, 2015, our short-term debt primarily reflects $549 of borrowings under our accounts receivable securitization facility.

[2] The difference between the June 30, 2015 carrying value of the 4 percent Convertible Senior Notes and the $8 principal amount reflects the $1 unamortized portion of the original issue discount recognized upon issuance of the notes, which is being amortized through the maturity date of November 15, 2015. Because the 4 percent Convertible Senior Notes were redeemable at June 30, 2015, an amount equal to the $1 unamortized portion of the original issue discount is separately classified in our condensed consolidated balance sheets and referred to as “temporary equity.” During the six months ended June 30, 2015, $26 of our 4 percent Convertible Senior Notes were redeemed. We recognized a loss of approximately $1 in interest expense, net upon redemption. The loss represented the difference between the net carrying amount and the fair value of the debt component of the notes. Holders of the 4 percent Convertible Senior Notes have the right to redeem the notes prior to November 15, 2015 at a conversion price of $11.11 per share of common stock. Since July 1, 2015 (the beginning of the third quarter), none of the 4 percent Convertible Senior Notes have been redeemed.

[3] At June 30, 2015, $680 was available under our ABL facility, net of $49 of letters of credit. The interest rate applicable to the ABL facility was 1.8 percent at June 30, 2015. During the six months ended June 30, 2015, the monthly average amount outstanding under the ABL facility was $1.2 billion, and the weighted-average interest rate thereon was 2.0 percent. The maximum month-end amount outstanding under the ABL facility during the six months ended June 30, 2015 was $1.8 billion. In March 2015, the ABL facility was amended, primarily to increase the facility size and to extend the maturity date. The size of the facility was increased to $2.5 billion. All amounts borrowed under the ABL facility must be repaid on or before March 2020.

[4] In April 2015, we redeemed all of our 5 3/4 percent Senior Secured Notes and 8 3/8 percent Senior Subordinated Notes. Upon redemption, we recognized an aggregate loss of $106 in interest expense, net. The loss represented the difference between the net carrying amount and the total purchase price of the notes.

[5] In March 2015, URNA issued $1.0 billion aggregate principal amount of 4 5/8 percent Senior Secured Notes (the “4 5/8 percent Notes”) which are due July 15, 2023. The net proceeds from issuance were approximately $990 (after deducting offering expenses). The 4 5/8 percent Notes are guaranteed by Holdings and certain domestic subsidiaries of URNA and are secured on a second-priority basis by liens on substantially all of URNA’s and the guarantors’ assets that secure the ABL facility, subject to certain exceptions. The 4 5/8 percent Notes may be redeemed on or after July 15, 2018, at specified redemption prices that range from 103.469 percent in 2018, to 100 percent in 2021 and thereafter, plus accrued and unpaid interest, if any. The indenture governing the 4 5/8 percent Notes contains certain restrictive covenants, including, among others, limitations on (i) liens; (ii) additional indebtedness; (iii) mergers, consolidations and acquisitions; (iv) sales, transfers and other dispositions of assets; (v) loans and other investments; (vi) dividends and other distributions, stock repurchases and redemptions and other restricted payments; (vii) restrictions affecting subsidiaries; (viii) transactions with affiliates; and (ix) designations of unrestricted subsidiaries, as well as a requirement to timely file periodic reports with the SEC. The indenture also includes covenants relating to the grant of and maintenance of liens for the benefit of the notes collateral agent. Each of the restrictive covenants is subject to important exceptions and qualifications that would allow URNA and its subsidiaries to engage in these activities under certain conditions. The indenture also requires that, in the event of a change of control (as defined in the indenture), URNA must make an offer to purchase all of the then-outstanding 4 5/8 percent Notes tendered at a purchase price in cash equal to 101 percent of the principal amount thereof, plus accrued and unpaid interest, if any, thereon.

[6] In April 2015, we redeemed $350 principal amount of our 8 1/4 percent Senior Notes. Upon redemption, we recognized a loss of $15 in interest expense, net. The loss represented the difference between the net carrying amount and the total purchase price of the redeemed notes.

[7] In March 2015, URNA issued $800 aggregate principal amount of 5 1/2 percent Senior Notes (the “5 1/2 percent Notes”) which are due July 15, 2025. The net proceeds from the issuance were approximately $792 (after deducting offering expenses). The 5 1/2 percent Notes are unsecured and are guaranteed by Holdings and certain domestic subsidiaries of URNA. The 5 1/2 percent Notes may be redeemed on or after July 15, 2020, at specified redemption prices that range from 102.75 percent in 2020, to 100 percent in 2023 and thereafter, plus accrued and unpaid interest, if any. The indenture governing the 5 1/2 percent Notes contains certain restrictive covenants, including, among others, limitations on (i) liens; (ii) additional indebtedness; (iii) mergers, consolidations and acquisitions; (iv) sales, transfers and other dispositions of assets; (v) loans and other investments; (vi) dividends and other distributions, stock repurchases and redemptions and other restricted payments; (vii) restrictions affecting subsidiaries; (viii) transactions with affiliates; and (ix) designations of unrestricted subsidiaries, as well as a requirement to timely file periodic reports with the SEC. Each of the restrictive covenants is subject to important exceptions and qualifications that would allow URNA and its subsidiaries to engage in these activities under certain conditions. The indenture also requires that, in the event of a change of control (as defined in the indenture), URNA must make an offer to purchase all of the then-outstanding 5 1/2 percent Notes tendered at a purchase price in cash equal to 101 percent of the principal amount thereof, plus accrued and unpaid interest, if any, thereon.

[8] At June 30, 2015, $1 was available under our accounts receivable securitization facility. The interest rate applicable to the accounts receivable securitization facility was 0.9 percent at June 30, 2015. During the six months ended June 30, 2015, the monthly average amount outstanding under the accounts receivable securitization facility was $456, and the weighted-average interest rate thereon was 0.8 percent. The maximum month-end amount outstanding under the accounts receivable securitization facility during the six months ended June 30, 2015 was $550. Borrowings under the accounts receivable securitization facility are permitted only to the extent that the face amount of the receivables in the collateral pool, net of applicable reserves, exceeds the outstanding loans. As of June 30, 2015, there were $627 of receivables, net of applicable reserves, in the collateral pool.