Commitments and Contingencies - Royalty Obligations (Details) - Corporate and other $ in Millions	9 Months Ended
	Sep. 30, 2015 USD ($) location	Dec. 31, 2014 USD ($)
Other commitments
Letters of credit surety bonds and bank guarantees, outstanding	$ 1,954	$ 1,865
Minimum Royalty Obligations
Minimum Royalty Obligations
Number of mines subject to minimum royalty obligations | location	1
Minimum royalty obligation for remainder of current year	$ 30
Minimum royalty obligation in year two	32
Minimum royalty obligation in year three	32
Minimum royalty obligation in year four	32
Minimum royalty obligation in year five	32
Minimum royalty obligation in total thereafter	$ 190