Long-Term Debt (Indebtedness Table) (Details) (USD $)	3 Months Ended		9 Months Ended				9 Months Ended					9 Months Ended			9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Sep. 30, 2014 ENLC Credit Facility [Member]	Sep. 30, 2014 2.7% Senior Notes due 2019 [Member]	Sep. 30, 2014 7.125% Senior Notes due 2022 [Member]		Sep. 20, 2014 7.125% Senior Notes due 2022 [Member]	Jul. 20, 2014 7.125% Senior Notes due 2022 [Member]	Sep. 30, 2014 4.4% Senior Notes due 2024 [Member]	Sep. 30, 2014 Unsecured Debt [Member]	Sep. 30, 2014 Other Debt Obligations [Member]	Sep. 30, 2014 September Redemption [Member] 7.125% Senior Notes due 2022 [Member]
Debt Instrument [Line Items]
Debt Instrument, Repurchase Date							Mar. 01, 2019					Jan. 01, 2024	Oct. 01, 2043		Sep. 20, 2014
Debt Instrument, Repurchased Face Amount										$ 15,500,000	$ 18,500,000
Line of Credit Facility, Amount Outstanding	371,000,000		371,000,000			80,500,000								26,300,000
Senior Notes							397,300,000	185,100,000	[1]			446,500,000	346,800,000
Long-term Debt	1,853,900,000		1,853,900,000											26,700,000
Long-term Debt, Excluding Current Maturities	1,853,900,000		1,853,900,000		0
Debt Instrument, Repurchase Amount										17,000,000	20,000,000
Gain on Extinguishment of Debt	$ 2,400,000	$ 0	$ 3,200,000	$ 0

[1] September 30, 2014Partnership bank credit facility (due 2019), interest based on Prime and/or LIBOR plus an applicable margin, interest rate at September 30, 2014 was 1.9%$371.0Company bank credit facility (due 2019), interest based on LIBOR plus an applicable margin, interest rate at September 30, 2014 was 1.9%80.5Senior unsecured notes (due 2019), net of discount of $2.7 million, which bear interest at the rate of 2.70%397.3Senior unsecured notes (due 2022), including a premium of $22.6 million, which bear interest at the rate of 7.125% 185.1Senior unsecured notes (due 2024), net of discount of $3.5 million, which bear interest at the rate of 4.40%446.5Senior unsecured notes (due 2044), net of discount of $3.3 million, which bear interest at the rate of 5.60%346.8Other debt26.7Debt classified as long-term$1,853.9