Discontinued Operations (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Disposal group
Income (loss) from discontinued operations	$ 17	$ 3	$ 34	$ (16)
Net operating cash used in discontinued operations			(9)	(10)
Holloway Mining Company \| Discontinued operations disposed of by sale
Disposal group
Income (loss) from discontinued operations	17	(3)	34	(16)
Discontinued operations, income tax expense (benefit)	$ 7	$ (2)	15	(7)
Net operating cash used in discontinued operations			$ (9)	$ (10)

Amount of tax expense (benefit) related to a discontinued operation. Includes, but is not limited to, tax expense (benefit) related to income (loss) from operations during the phase-out period, tax expense (benefit) related to gain (loss) on disposal, tax expense (benefit) related to gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and tax expense (benefit) related to adjustments of a prior period gain (loss) on disposal.

Amount after tax of income (loss) from a discontinued operation including the portion attributable to the noncontrolling interest. Includes, but is not limited to, the income (loss) from operations during the phase-out period, gain (loss) on disposal, gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and adjustments to a prior period gain (loss) on disposal.

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+ Details