Capital and Accumulated Other Comprehensive Income (Loss) (Partnership Units Narrative) (Details) $ in Millions	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Class of Stock [Line Items]
Common stock conversion ratio	1
Redemption value of LP units	$ 887.0	$ 226.3
Digital Realty Trust, L.P.
Class of Stock [Line Items]
Common stock conversion ratio	1
Redemption value of LP units	$ 887.0	$ 226.3

Redemption value, as if currently redeemable, of redeemable noncontrolling interest for common shares, units or ownership interests classified as temporary equity and the election has been made to accrete changes in redemption value to the earliest redemption date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 480
-SubTopic 10
-Section S99
-Paragraph 3A
-Subparagraph 24(b)
-URI http://asc.fasb.org/extlink&oid=65877616&loc=SL6540498-122764

Name:	us-gaap_RedeemableNoncontrollingInterestEquityCommonRedemptionValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant