CONDENSED CONSOLIDATED STATEMENTS OF INCOME Net Income Per Unit: (Common Units, USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Common Units
Net income per unit:
Net income per unit (in units)	$ 0.31	$ 0.44
Weighted-average number of units outstanding:
Weighted-average number of units outstanding (in units)	244.3	243.3
Net Income per Unit:
Cash distribution declared and paid to common units (in units)	$ 0.10	$ 0.10