Stockpiles and Ore on Leach Pads - Stockpiles and Ore on Leach Pads (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Stockpiles And Ore On Leach Pads [Line Items]
Current stockpiles and ore on leach pads	$ 689	$ 805
Long-term stockpiles and ore on leach pads	2,758	2,680
Stockpiles [Member]
Stockpiles And Ore On Leach Pads [Line Items]
Current stockpiles and ore on leach pads	423	580
Long-term stockpiles and ore on leach pads	2,517	2,434
Ore on Leach Pads [Member]
Stockpiles And Ore On Leach Pads [Line Items]
Current stockpiles and ore on leach pads	266	225
Long-term stockpiles and ore on leach pads	$ 241	$ 246