Basis of Presentation and Summary of Significant Accounting Policies Significant Accounting Policies - Accounts Receivable Table (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other receivables	$ 150	$ 168
Oil and gas joint interest billing receivables, current	417	592
Accounts Receivable, Related Parties	62	23
Allowance for Doubtful Accounts Receivable	(18)	(19)
Accounts receivable, net	2,222	2,245
Exploration and Production
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other receivables	1,548	1,457
Oilfield Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other receivables	$ 63	$ 24