Summary of Significant Accounting Policies (Basic and Diluted Income) (Details) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net Income (Loss) Available to Common Stockholders, Basic	$ 299,915	$ 428,972	$ 383,729
Participating Securities, Distributed and Undistributed Earnings (Loss), Basic	(1,447)	(1,487)	(1,675)
Net Income Loss Attributable To Common Stockholders Basic	298,468	427,485	382,054
Participating Securities, Distributed and Undistributed Earnings (Loss), Diluted	0	1,487	1,675
Noncontrolling Interest in Net Income (Loss) Operating Partnerships, Redeemable	2,663	3,678	3,528
Net Income (Loss) Available to Common Stockholders, Diluted	$ 301,131	$ 432,650	$ 387,257
Weighted Average Number of Shares Outstanding, Basic	370,057	362,234	357,569
Weighted Average Limited Partnership Units Outstanding, Basic	3,303	3,118	3,290
Weighted Average Number Diluted Shares Outstanding Adjustment	796	1,987	2,438
Weighted Average Number of Shares Outstanding, Diluted	374,156	367,339	363,297
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	$ 302,578	$ 432,650	$ 387,257
Participating Securities, Distributed and Undistributed Earnings (Loss), Basic	(1,447)	(1,487)	(1,675)
Net Income Loss Attributable To Common Unitholders Basic	301,131	431,163	385,582
Participating Securities, Distributed and Undistributed Earnings (Loss), Diluted	0	1,487	1,675
Diluted Net Income Loss Attributable To Common Unitholders	$ 301,131	$ 432,650	$ 387,257
Weighted Average Number of Shares Outstanding, Basic	373,360	365,352	360,859
Weighted Average Number Diluted Shares Outstanding Adjustment	796	1,987	2,438
Weighted Average Number of Shares Outstanding, Diluted	374,156	367,339	363,297