Incentive Compensation Plans (Details) (USD $)	12 Months Ended										1 Months Ended	12 Months Ended					1 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Phantom units	Dec. 31, 2011 Phantom units	Dec. 31, 2010 Phantom units	Dec. 31, 2012 Distribution equivalent rights	Dec. 31, 2011 Distribution equivalent rights	Dec. 31, 2010 Distribution equivalent rights	Dec. 31, 2012 2008 LTIP	Apr. 30, 2010 2008 LTIP TSR Performance Units	Dec. 31, 2012 2008 LTIP TSR Performance Units	Dec. 31, 2011 2008 LTIP TSR Performance Units	Dec. 31, 2010 2008 LTIP TSR Performance Units	Jan. 31, 2012 2008 LTIP TSR Performance Units	Jan. 31, 2011 2008 LTIP TSR Performance Units	Jan. 31, 2010 2008 LTIP Unrestricted units	Dec. 31, 2012 2008 LTIP Performance units	Dec. 31, 2011 2008 LTIP Performance units	Dec. 31, 2010 2008 LTIP Performance units	Dec. 31, 2012 2002 LTIP Plan Phantom units	Dec. 31, 2011 2002 LTIP Plan Phantom units	Dec. 31, 2010 2002 LTIP Plan Phantom units	Dec. 31, 2012 2008 LTIP and 2006 Hydrocarbon Plan Phantom units	Dec. 31, 2011 2008 LTIP and 2006 Hydrocarbon Plan Phantom units	Dec. 31, 2010 2008 LTIP and 2006 Hydrocarbon Plan Phantom units
Share-based compensation arrangement by share-based payment award
Total share-based compensation expense	$ 14,656,000	$ 13,925,000	$ 16,784,000	$ 14,615,000	$ 13,479,000	$ 15,319,000	$ 41,000	$ 446,000	$ 1,465,000			$ 2,200,000	$ 4,800,000	$ 4,500,000			$ 4,800,000	$ 0	$ 0	$ 0
Total compensation expense not yet recognized										12,700,000
Unrecognized compensation costs on unvested awards, weighted average period of recognition										1 year
Common units provided for issuance to employees and affiliates as share-based payment awards										3,700,000
Performance period used in computation of total unitholder return												3 years
Number of units that vested based on actual performance with regards to the market criteria															141,000	141,000
Number of units that vested based on actual performance with regards to the market criteria and performance criteria															35,250	35,250
Vesting period of share-based awards																		3 years			3 years			3 years
Cash paid for taxes related to vesting of share-based payment awards related to tax withholding for share-based compensation	8,067,000	6,354,000	3,834,000																			400,000	400,000	8,100,000	6,000,000	3,400,000
Unit activity
Unvested at the beginning of the period (in units)												141,000												935,509
Granted (in units)											282,000	35,250					166,000							296,545
Vested (in units)												(176,250)												(386,334)
Forfeited (in units)																								(158,144)
Unvested at the end of the period (in units)													141,000											687,576	935,509
Weighted-average Grant-date Fair Value
Unvested at the beginning of the period (in dollars per unit)																								$ 28.59
Granted (in dollars per unit)																								$ 57.50
Vested (in dollars per unit)																								$ 26.98
Forfeited (in dollars per unit)																								$ 11.95
Unvested at the end of the period (in dollars per unit)																								$ 45.79	$ 28.59
Other Award Information
Total fair value of phantom units vested during the period												6,500,000	4,900,000									1,000,000	1,300,000	10,400,000	10,700,000	9,800,000
Total intrinsic value of phantom units vested during the period												$ 6,500,000	$ 4,900,000									$ 1,000,000	$ 1,300,000	$ 10,400,000	$ 10,700,000	$ 9,800,000