Impairments - Narrative (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Sep. 30, 2012
Significant Acquisitions and Disposals [Line Items]
Impairment of natural gas and oil properties	$ 0	$ 3,315	$ 0
Effects of Cash Flow Hedges Considered in Calculation Ceiling Limitation, Amount				279
Impairments of fixed assets and other	546	340	46
Other Asset Impairment Charges	87
Third Party [Member]
Significant Acquisitions and Disposals [Line Items]
Gain (Loss) on Contract Termination	15
Net Acreage Maintenance Commitment [Member]
Significant Acquisitions and Disposals [Line Items]
Other Asset Impairment Charges	2	26
Drilling Rigs [Member]
Significant Acquisitions and Disposals [Line Items]
Number of repurchased equipment	23
Payments to Acquire Property, Plant, and Equipment	141
Repurchase of Rigs [Member]
Significant Acquisitions and Disposals [Line Items]
Equipment Owned		25
Assets Held-for-sale [Member] | Drilling Rigs [Member]
Significant Acquisitions and Disposals [Line Items]
Number of repurchased equipment	2
Leasehold Improvements [Member]
Significant Acquisitions and Disposals [Line Items]
Impairment of Long-Lived Assets to be Disposed of	22
Land and Building [Member]
Significant Acquisitions and Disposals [Line Items]
Impairments of fixed assets and other	366	248	3
Drilling Rigs [Member]
Significant Acquisitions and Disposals [Line Items]
Impairment of Long-Lived Assets to be Disposed of	27	26
Payments to Acquire Property, Plant, and Equipment	141
Gain (Loss) on Contract Termination	22
Drilling Rigs [Member] | Repurchase of Rigs [Member]
Significant Acquisitions and Disposals [Line Items]
Payments to Acquire Property, Plant, and Equipment		36
Gain (Loss) on Contract Termination		25
Tubular Goods [Member]
Significant Acquisitions and Disposals [Line Items]
Impairment of Long-Lived Assets to be Disposed of		9
Gas Gathering and Processing Equipment [Member]
Significant Acquisitions and Disposals [Line Items]
Impairment of Long-Lived Assets to be Disposed of	22	6	43
Impairments of fixed assets and other	22	6	43
Other Asset Impairment Charges	26
Property, Plant and Equipment, Other Types
Significant Acquisitions and Disposals [Line Items]
Other Asset Impairment Charges	16
Selling and Marketing Expense [Member]
Significant Acquisitions and Disposals [Line Items]
Other Asset Impairment Charges	28
In the Oklahoma City Area [Member] | Land and Building [Member]
Significant Acquisitions and Disposals [Line Items]
Impairments of fixed assets and other	69
In the Oklahoma City Area [Member] | Land and Building [Member] | Assets Held-for-sale [Member]
Significant Acquisitions and Disposals [Line Items]
Impairment of Long-Lived Assets to be Disposed of	186
In the Fort Worth Area [Member] | Land and Building [Member]
Significant Acquisitions and Disposals [Line Items]
Impairments of fixed assets and other		10
In the Fort Worth Area [Member] | Land and Building [Member] | Assets Held-for-sale [Member]
Significant Acquisitions and Disposals [Line Items]
Impairment of Long-Lived Assets to be Disposed of	86
Outside the Oklahoma City Area [Member] | Land and Building [Member]
Significant Acquisitions and Disposals [Line Items]
Impairments of fixed assets and other	$ 15