Summary of Significant Accounting Policies (Basic and Diluted Income) (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net Income (Loss) Available to Common Stockholders, Basic	$ 63,896	$ 53,025	$ 193,845	$ 72,963	$ 188,419	$ 165,269	$ 1,210,543	$ 70,200	$ 383,729	$ 1,634,431	$ 312,143
Participating Securities, Distributed and Undistributed Earnings (Loss), Basic									(1,675)	(3,981)	(2,356)
Net Income Loss Attributable To Common Stockholders Basic									382,054	1,630,450	309,787
Participating Securities, Distributed and Undistributed Earnings (Loss), Diluted									1,675	3,981	2,356
Noncontrolling Interest in Net Income (Loss) Operating Partnerships, Redeemable									3,528	15,176	3,089
Net Income (Loss) Available to Common Stockholders, Diluted									$ 387,257	$ 1,649,607	$ 315,232
Weighted Average Number of Shares Outstanding, Basic	358,561	357,898	357,054	356,740	356,204	355,905	355,647	355,282	357,569	355,762	349,942
Weighted Average Limited Partnership Units Outstanding, Basic									3,290	3,303	3,481
Weighted Average Number Diluted Shares Outstanding Adjustment									2,438	2,946	3,653
Weighted Average Number of Shares Outstanding, Diluted	362,536	361,410	362,741	360,400	360,244	362,102	361,981	360,700	363,297	362,011	357,076
Duke Realty Limited Partnership [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net Income (Loss) Available to Common Stockholders, Basic	$ 64,422	$ 53,520	$ 195,669	$ 73,646	$ 190,168	$ 166,804	$ 1,221,783	$ 70,852	$ 387,257	$ 1,649,607	$ 315,232
Participating Securities, Distributed and Undistributed Earnings (Loss), Basic									(1,675)	(3,981)	(2,356)
Net Income Loss Attributable To Common Unitholders Basic									385,582	1,645,626	312,876
Participating Securities, Distributed and Undistributed Earnings (Loss), Diluted									1,675	3,981	2,356
Diluted Net Income Loss Attributable To Common Unitholders									$ 387,257	$ 1,649,607	$ 315,232
Weighted Average Number of Shares Outstanding, Basic	361,672	361,200	360,447	360,095	359,491	359,206	358,952	358,598	360,859	359,065	353,423
Weighted Average Number Diluted Shares Outstanding Adjustment									2,438	2,946	3,653
Weighted Average Number of Shares Outstanding, Diluted	362,536	361,410	362,741	360,400	360,244	362,102	361,981	360,700	363,297	362,011	357,076