Income per Unit (Schedule of Antidilutive Securities Excluded From Computation of Earnings Per Share) (Details) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (in shares)	13,559,863	16,421,253	20,118,783
Potentially dilutive Series E Cumulative Redeemable Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (in shares)	0	2,880,254	4,301,438
Potentially dilutive Series F Cumulative Redeemable Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (in shares)	463,301	1,939,905	2,727,962
Potentially dilutive Series G Cumulative Redeemable Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (in shares)	2,261,153	2,652,503	3,730,042
Potentially dilutive Series H Cumulative Redeemable Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (in shares)	3,313,484	3,886,966	5,465,987
Potentially dilutive Series I Cumulative Redeemable Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (in shares)	2,263,799	2,655,607	1,235,063
Potentially dilutive Series J Cumulative Redeemable Preferred Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (in shares)	720,803	0	0
Digital Realty Trust, L.P.
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (in shares)	9,563,313	14,015,235	17,460,492
Digital Realty Trust, L.P. | Potentially dilutive Series C Cumulative Redeemable Perpetual Preferred Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (in shares)	540,773	0	0
Digital Realty Trust, L.P. | Potentially dilutive Series E Cumulative Redeemable Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (in shares)	0	2,880,254	4,301,438
Digital Realty Trust, L.P. | Potentially dilutive Series F Cumulative Redeemable Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (in shares)	463,301	1,939,905	2,727,962
Digital Realty Trust, L.P. | Potentially dilutive Series G Cumulative Redeemable Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (in shares)	2,261,153	2,652,503	3,730,042
Digital Realty Trust, L.P. | Potentially dilutive Series H Cumulative Redeemable Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (in shares)	3,313,484	3,886,966	5,465,987
Digital Realty Trust, L.P. | Potentially dilutive Series I Cumulative Redeemable Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (in shares)	2,263,799	2,655,607	1,235,063
Digital Realty Trust, L.P. | Potentially dilutive Series J Cumulative Redeemable Preferred Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (in shares)	720,803	0	0