Partners' Capital and Distributions - Exchange Rights and Shares Activity (Details) - shares	3 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018
Class A Shares
Activity for Class A shares, Class B shares and Class C shares
Balance, beginning of period (shares)	166,817,333	159,485,588	159,485,588	157,954,130	157,019,038	156,111,139
Exchange Right exercises (shares)	15,173,490	7,331,745		1,195,405	935,092	907,899
Other (shares)	15,186			11,250
Balance, end of period (shares)	182,006,009	166,817,333	159,485,588	159,160,785	157,954,130	157,019,038
Class B Shares
Activity for Class A shares, Class B shares and Class C shares
Balance, beginning of period (shares)	99,987,150	119,512,666	119,604,338	122,018,330	126,037,449	126,984,572
Exchange Right exercises (shares)	(15,173,490)	(7,331,745)		(1,195,405)	(935,092)	(907,899)
Redemption Right exercises (shares)	(16,254,598)	(12,193,771)	(91,672)	(183,225)	(3,084,027)	(39,224)
Balance, end of period (shares)	68,559,062	99,987,150	119,512,666	120,639,700	122,018,330	126,037,449
Class C Shares
Activity for Class A shares, Class B shares and Class C shares
Balance, beginning of period (shares)	530,053,993	517,256,766	516,938,280	515,460,375	512,376,348	510,925,432
Redemption Right exercises (shares)	16,254,598	12,193,771	91,672	183,225	3,084,027	39,224
Issuance of Series A preferred units by a subsidiary (shares)						1,393,926
Other (shares)	588,771	603,456	226,814	494,400		17,766
Balance, end of period (shares)	546,897,362	530,053,993	517,256,766	516,138,000	515,460,375	512,376,348