Debt of the Operating Partnership (Unsecured Term Loan) (Narrative) (Details) - USD ($)		9 Months Ended
	Jan. 15, 2016	Sep. 30, 2018	Dec. 31, 2017	Apr. 16, 2012
Unsecured Term Loans
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity	$ 1.55
Digital Realty Trust, L.P.
Debt Instrument [Line Items]
Long-term debt, gross		$ 9,242,935,000
Digital Realty Trust, L.P. | Unsecured Term Loans
Debt Instrument [Line Items]
Long-term debt, gross		$ 1,356,702,000	$ 1,425,117,000
Digital Realty Trust, L.P. | Unsecured term loan — 5-year
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity	$ 1,250,000,000.00
Debt instrument term	5 years
Interest rate basis spread		1.10%
Digital Realty Trust, L.P. | Unsecured term loan — 5-year | Unsecured Term Loans
Debt Instrument [Line Items]
Debt instrument term		5 years
Interest rate basis spread		1.10%
Long-term debt, gross		$ 1,056,702,000	1,125,117,000
Digital Realty Trust, L.P. | Unsecured term loan — 7-year
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity	$ 300,000,000
Debt instrument term	7 years
Interest rate basis spread		1.55%
Digital Realty Trust, L.P. | Unsecured term loan — 7-year | Unsecured Term Loans
Debt Instrument [Line Items]
Debt instrument term		7 years
Interest rate basis spread		1.55%
Long-term debt, gross		$ 300,000,000	$ 300,000,000
Digital Realty Trust, L.P. | Unsecured Term Loans
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity		1,550,000,000.00		$ 1,000,000,000.0
Credit facility, maximum borrowing capacity, subject to receipt of lender commitments and other conditions		$ 1,800,000,000.0