Quarterly Financial Data (Unaudited) (Schedule of Quarterly Financial Information) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 13,573	$ 14,514	$ 14,118	$ 11,882	$ 11,451	$ 9,984	$ 9,427	$ 9,661	$ 54,087	$ 40,523	$ 31,792
Operating income	1,419	1,703	1,126	1,100	289	931	743	758	5,348	2,721	1,851
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	852	1,393	659	726	1,158	741	314	330	3,630	2,543	462
Net income	852	1,391	633	489	1,168	758	121	319	3,365	2,366	0
Limited Partners’ interest in net income	$ 617	$ 370	$ 330	$ 341	$ 239	$ 240	$ 204	$ 232	$ 1,658	$ 915	$ 983
Basic	$ 0.26	$ 0.32	$ 0.30	$ 0.31	$ 0.22	$ 0.22	$ 0.19	$ 0.22	$ 1.16	$ 0.85	$ 0.94
Diluted	0.26	0.32	0.30	0.31	0.22	0.22	0.18	0.21	1.15	0.83	0.92
Basic	0.26	0.32	0.30	0.32	0.22	0.22	0.20	0.22	1.17	0.86	0.95
Diluted	$ 0.26	$ 0.32	$ 0.30	$ 0.32	$ 0.22	$ 0.22	$ 0.19	$ 0.21	$ 1.16	$ 0.84	$ 0.93