Fair Value of Financial Instruments (Cost and Equity Method Investments) (Narrative) (Details) - USD ($)	1 Months Ended	3 Months Ended		13 Months Ended
	Apr. 30, 2016	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Dec. 31, 2015
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Aggregate carrying value, cost and equity method investment assets		$ 20,400,000		$ 20,400,000	$ 16,700,000
Other comprehensive loss, unrecognized unrealized fair market value losses, net of tax		8,010,000	$ 0
Other long-term liabilities, equity method investments		77,361,000		77,361,000	68,119,000
Equity method investments, earnings related to expected recoveries		3,066,000	(585,000)
Unconsolidated affiliates, financing commitments, amounts paid		1,514,000	$ 31,959,000
Performance Guarantees [Member]
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Guarantees issued, related parties		147,800,000		147,800,000	539,300,000
Credit Facility [Member]
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Letters of credit issued		403,800,000		403,800,000	292,800,000
Equity Method Investees [Member] | Waha JVs [Member]
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Revenue, related parties		10,300,000
Receivables, related parties		8,300,000		8,300,000
Other long-term liabilities, equity method investments		18,000,000		18,000,000	4,400,000
Equity Method Investees [Member] | Waha JVs [Member] | Interest Rate Swaps [Member]
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Other comprehensive loss, unrecognized unrealized fair market value losses, before tax		13,000,000
Other comprehensive loss, unrecognized unrealized fair market value losses, net of tax		8,000,000
Equity Method Investees [Member] | Waha JVs [Member] | Credit Facility [Member]
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Letters of credit issued		155,000,000		155,000,000	86,000,000
Equity Method Investees [Member] | Waha JVs [Member] | Credit Facility [Member] | Subsequent Event [Member]
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Letters of credit issued	$ 165,000,000
Letters of credit issued, increase	$ 10,000,000
Equity Method Investees [Member] | Waha JVs [Member] | Credit Facility [Member] | Financial Standby [Member]
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Letters of credit issued		$ 78,000,000		$ 78,000,000	$ 78,000,000
Equity Method Investees [Member] | Pacer [Member]
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Number of joint ventures		2		2
Equity method investment, expected collection period (in months)		12 months
Equity Method Investees [Member] | Pacer [Member] | Canadian Dollars [Member]
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Receivables, related parties		$ 4,000,000		$ 4,000,000
Equity Method Investees [Member] | Pacer [Member] | Canadian Dollars [Member] | Financial Support [Member]
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Equity method investments, earnings related to expected recoveries				3,600,000
Unconsolidated affiliates, financing commitments, amounts paid				39,900,000
Unconsolidated affiliates, financing commitments, amounts repaid				12,800,000
Equity Method Investees [Member] | Pacer [Member] | Financial Guarantees [Member] | Canadian Dollars [Member]
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Guarantees issued, related parties		$ 0		$ 0
Equity Method Investees [Member] | Pacer [Member] | Performance Guarantees [Member]
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Construction projects, percentage complete		100.00%		100.00%
Immediate Family Member of Management or Principal Owner [Member] | Cost Method Investment [Member] | Cross Country Pipeline [Member]
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Cost method investment, original cost		$ 15,000,000		$ 15,000,000