Capital And Comprehensive Income (Narrative) (Details) (USD $) In Millions, except Share data, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011
Capital and Accumulated Other Comprehensive Income (Loss) [Line Items]
Acquisition amount	$ 1,462.2
Digital Realty Trust, L.P. [Member]
Capital and Accumulated Other Comprehensive Income (Loss) [Line Items]
Redemption value of common units	290.1		291.5
Series F Cumulative Convertible Preferred Units [Member]
Capital and Accumulated Other Comprehensive Income (Loss) [Line Items]
Preferred stock, issued	7,300,000		0
Preferred stock, dividend rate	6.625%		6.625%
Preferred stock dividend per share amount	$ 1.656	$ 1.65625
Preferred stock, liquidation preference per share/unit	$ 25.00		$ 25.00
Series F Cumulative Convertible Preferred Units [Member] | Digital Realty Trust, L.P. [Member]
Capital and Accumulated Other Comprehensive Income (Loss) [Line Items]
Preferred stock, dividend rate	6.625%		6.625%
Preferred stock dividend per share amount	$ 1.656
Preferred stock, liquidation preference per share/unit	$ 25.00		$ 25.00
April 5, 2012 [Member] | Series F Cumulative Convertible Preferred Units [Member]
Capital and Accumulated Other Comprehensive Income (Loss) [Line Items]
Issuance date	Apr. 05, 2012
Preferred stock, issued	7,300,000
Preferred stock, dividend rate	6.625%
Preferred stock dividend per share amount	$ 1.65625
Preferred stock, liquidation preference per share/unit	$ 25.00
Preferred stock, distribution payable date	Jun. 29, 2012
Preferred stock, dividends in arrears	$ 0.395660
Preferred stock, redemption date	Apr. 05, 2017
Redemption price	$ 25.00
April 5, 2012 [Member] | Series F Cumulative Convertible Preferred Units [Member] | Digital Realty Trust, L.P. [Member]
Capital and Accumulated Other Comprehensive Income (Loss) [Line Items]
Issuance date	Apr. 05, 2012
Preferred stock, issued	7,300,000
Preferred stock, dividend rate	6.625%
Preferred stock dividend per share amount	$ 1.65625
Preferred stock, liquidation preference per share/unit	$ 25.00
Preferred stock, distribution payable date	Jun. 29, 2012
Preferred stock, dividends in arrears	$ 0.39566
Preferred stock, redemption date	Apr. 05, 2017
Redemption price	$ 25.00
April 18, 2012 [Member] | Series F Cumulative Convertible Preferred Units [Member]
Capital and Accumulated Other Comprehensive Income (Loss) [Line Items]
Issuance date	Apr. 18, 2012
Preferred stock, issued	7,300,000
Preferred stock, dividend rate	6.625%
Preferred stock dividend per share amount	$ 1.656250
Preferred stock, liquidation preference per share/unit	$ 25.00
Preferred stock, distribution payable date	Jun. 29, 2012
Preferred stock, dividends in arrears	$ 0.395660
Preferred stock, redemption date	Apr. 05, 2017
Redemption price	$ 25.00
April 18, 2012 [Member] | Series F Cumulative Convertible Preferred Units [Member] | Digital Realty Trust, L.P. [Member]
Capital and Accumulated Other Comprehensive Income (Loss) [Line Items]
Issuance date	Apr. 18, 2012
Preferred stock, issued	7,300,000
Preferred stock, dividend rate	6.625%
Preferred stock dividend per share amount	$ 1.656250
Preferred stock, liquidation preference per share/unit	$ 25.00
Preferred stock, distribution payable date	Jun. 29, 2012
Preferred stock, dividends in arrears	$ 0.395660
Preferred stock, redemption date	Apr. 05, 2017
Redemption price	$ 25.00
Noncontrolling Interests In Consolidated Joint Ventures [Member]
Capital and Accumulated Other Comprehensive Income (Loss) [Line Items]
Date of acquisition	May 04, 2012
Acquisition amount	12.4
Noncontrolling Interests In Consolidated Joint Ventures [Member] | Digital Realty Trust, L.P. [Member]
Capital and Accumulated Other Comprehensive Income (Loss) [Line Items]
Date of acquisition	May 04, 2012
Acquisition amount	$ 12.4