Basis of Presentation and Summary of Significant Accounting Policies - Narrative (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Summary of Significant Accounting Policies [Line Items]
Equity Method Investment, Ownership Percentage	50.00%
Provision for Doubtful Accounts	$ 2,000,000	$ 0	$ 1,000,000
Goodwill		43,000,000
Bank Overdrafts	397,000,000	432,000,000
Unamortized Debt Issuance Expense	145,000,000	182,000,000
Gas Balancing Asset (Liability)	11,000,000	9,000,000
Premiums Receivable, Allowance for Doubtful Accounts, Write Offs Against Allowance	3,000,000
Natural Gas [Member]
Summary of Significant Accounting Policies [Line Items]
Percentage Of PortFolio	81.00%
Bronco Drilling Company Incorporated [Member]
Summary of Significant Accounting Policies [Line Items]
Goodwill	28,000,000
Horizon Drilling Services [Member]
Summary of Significant Accounting Policies [Line Items]
Goodwill	$ 15,000,000
Employee [Member] | Minimum
Summary of Significant Accounting Policies [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Employee [Member] | Maximum
Summary of Significant Accounting Policies [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	4 years
Director [Member]
Summary of Significant Accounting Policies [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years