Partners' Capital and Distributions (Details) - USD ($) $ / shares in Units, $ in Millions				6 Months Ended
	Aug. 14, 2015	May. 15, 2015	Feb. 13, 2015	Jun. 30, 2015	Jun. 30, 2014
Partners Capital and Distribution
Percentage of distribution amount to the general partner before incentive distributions				2.00%
Total distributions paid during the period				$ 811	$ 673
First Quarter Distribution
Partners Capital and Distribution
Distributions paid to Limited Partners		$ 272
Distributions paid to General Partner - 2%		6
Distributions paid to General Partner - Incentive		142
Total distributions paid during the period		$ 420
Distributions per limited partner unit		$ 0.6850
Distribution declared, date				Apr. 07, 2015
Distribution Date				May 15, 2015
Fourth Quarter Distribution
Partners Capital and Distribution
Distributions paid to Limited Partners			$ 254
Distributions paid to General Partner - 2%			5
Distributions paid to General Partner - Incentive			131
Total distributions paid during the period			$ 390
Distributions per limited partner unit			$ 0.6750
Distribution declared, date				Jan. 08, 2015
Distribution Date				Feb. 13, 2015
Subsequent Event | Second Quarter Distribution
Partners Capital and Distribution
Distributions paid to Limited Partners	$ 276
Distributions paid to General Partner - 2%	6
Distributions paid to General Partner - Incentive	146
Total distributions paid during the period	$ 428
Distributions per limited partner unit	$ 0.6950
Distribution declared, date				Jul. 07, 2015
Distribution Date				Aug. 14, 2015
Unitholders of record, date				Jul. 31, 2015