Business Segments (Details Textual) $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($) apartment_home Property Units Segment	Mar. 31, 2018 USD ($)	Dec. 31, 2018 Property Units
Business Segments (Textual) [Abstract]
Number of reportable segments | Segment	4
Capital additions related to segments | $	$ 75,898	$ 73,627
Operating Segments [Member] | Same Store [Member]
Business Segments (Textual) [Abstract]
Capital additions related to segments | $	30,211	27,522
Operating Segments [Member] | Redevelopment and Development [Member]
Business Segments (Textual) [Abstract]
Capital additions related to segments | $	39,048	43,481
Operating Segments [Member] | Acquisition [Member]
Business Segments (Textual) [Abstract]
Capital additions related to segments | $	3,868	483
Operating Segments [Member] | Other Real Estate [Member]
Business Segments (Textual) [Abstract]
Capital additions related to segments | $	$ 2,771	$ 2,141
Partially Owned Properties [Member]
Business Segments (Textual) [Abstract]
Number of owned and managed apartment communities in segments | Property	128
Number of apartment homes in apartment communities	34,349
Wholly And Partially Owned Consolidated Properties [Member]
Business Segments (Textual) [Abstract]
Number of owned and managed apartment communities in segments | Property	124
Number of apartment homes in apartment communities	34,207
Wholly And Partially Owned Consolidated Properties [Member] | Same Store [Member]
Business Segments (Textual) [Abstract]
Number of owned and managed apartment communities in segments	96
Number of apartment homes in apartment communities	28,039
Wholly And Partially Owned Consolidated Properties [Member] | Redevelopment and Development [Member]
Business Segments (Textual) [Abstract]
Number of owned and managed apartment communities in segments	7
Number of apartment homes in apartment communities	3,373
Wholly And Partially Owned Consolidated Properties [Member] | Acquisition [Member]
Business Segments (Textual) [Abstract]
Number of owned and managed apartment communities in segments	6
Number of apartment homes in apartment communities	1,480
Wholly And Partially Owned Consolidated Properties [Member] | Other Real Estate [Member]
Business Segments (Textual) [Abstract]
Number of owned and managed apartment communities in segments	15
Number of apartment homes in apartment communities	1,315
Variable Interest Entity, Primary Beneficiary [Member]
Business Segments (Textual) [Abstract]
Number of owned and managed apartment communities in segments | Property	9		9
Number of apartment homes in apartment communities | Units	3,592		3,592