Income per Share (Schedule of Antidilutive Securities Excluded from Computation of Earnings per Share) (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (shares)	19,036,184	12,245,217	19,993,742	11,487,387
Weighted average of Operating Partnership common units not owned by Digital Realty Trust, Inc.
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (shares)	8,170,912	3,266,451	8,268,382	2,566,766
Potentially dilutive Series C Cumulative Redeemable Perpetual Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (shares)	1,727,724	329,709	1,864,489	109,903
Potentially dilutive Series F Cumulative Redeemable Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (shares)	0	0	0	617,734
Potentially dilutive Series G Cumulative Redeemable Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (shares)	2,142,282	2,193,331	2,311,864	2,262,875
Potentially dilutive Series H Cumulative Redeemable Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (shares)	3,139,291	3,214,098	3,387,795	3,316,008
Potentially dilutive Series I Cumulative Redeemable Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (shares)	2,144,789	2,195,898	2,314,569	2,265,524
Potentially dilutive Series J Cumulative Redeemable Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (shares)	1,711,186	1,045,730	1,846,643	348,577