Fair Value Accounting - Fair Value on a Recurring Basis (Details) $ in Millions	Sep. 30, 2015 USD ($)
Recurring | Level 1
Assets:
Cash equivalents	$ 1,562
Assets	1,874
Recurring | Level 1 | Provisional copper and gold concentrate receivables
Assets:
Trade receivable, net	146
Recurring | Level 2
Liabilities:
Debt	5,851
Liabilities	5,966
Recurring | Level 2 | Foreign exchange forward contracts
Liabilities:
Derivative instruments, net	86
Recurring | Level 2 | Diesel forward contracts
Liabilities:
Derivative instruments, net	29
Recurring | Level 3
Assets:
Assets	26
Liabilities:
Liabilities	131
Recurring | Level 3 | Boddington Contingent Consideration
Liabilities:
Contingent consideration	10
Recurring | Level 3 | Holt property royalty
Liabilities:
Royalty	121
Recurring | Marketable Equity Securities | Extractive industries | Level 1
Assets:
Marketable securities	150
Recurring | Marketable Equity Securities | Other industries | Level 1
Assets:
Marketable securities	16
Recurring | Asset backed commercial paper | Level 3
Assets:
Marketable securities	19
Recurring | Auction rate securities | Level 3
Assets:
Marketable securities	7
Total | Recurring
Assets:
Cash equivalents	1,562
Assets	1,900
Liabilities:
Debt	5,851
Liabilities	6,097
Total | Recurring | Boddington Contingent Consideration
Liabilities:
Contingent consideration	10
Total | Recurring | Holt property royalty
Liabilities:
Royalty	121
Total | Recurring | Provisional copper and gold concentrate receivables
Assets:
Trade receivable, net	146
Total | Recurring | Foreign exchange forward contracts
Liabilities:
Derivative instruments, net	86
Total | Recurring | Diesel forward contracts
Liabilities:
Derivative instruments, net	29
Total | Recurring | Marketable Equity Securities | Extractive industries
Assets:
Marketable securities	150
Total | Recurring | Marketable Equity Securities | Other industries
Assets:
Marketable securities	16
Total | Recurring | Asset backed commercial paper
Assets:
Marketable securities	19
Total | Recurring | Auction rate securities
Assets:
Marketable securities	7
Carrying value
Liabilities:
Debt	$ 6,327