Basis of Presentation (Policies)	6 Months Ended
Basis of Presentation (Policies)	Jun. 30, 2015
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation Our interim consolidated financial statements have been prepared in accordance with the instructions to Form 10-Q and, therefore, do not necessarily include all information and footnotes necessary for a fair statement of our consolidated financial position, results of operations, and cash flows in accordance with accounting principles generally accepted in the United States, or GAAP.
Basis of Consolidation	Basis of Consolidation Our consolidated financial statements reflect all of our accounts, including those of our controlled subsidiaries and our tenancy-in-common interest, as described below. The portions of equity in consolidated subsidiaries that are not attributable, directly or indirectly, to us are presented as noncontrolling interests. All significant intercompany accounts and transactions have been eliminated. At June 30, 2015, we had an investment in a tenancy-in-common interest in various underlying international properties. Consolidation of this investment is not required as such interest does not qualify as a VIE and does not meet the control requirement required for consolidation. Accordingly, we account for this investment using the equity method of accounting. We use the equity method of accounting because the shared decision-making involved in a tenancy-in-common interest investment provides us with significant influence on the operating and financial decisions of this investment. We apply accounting guidance for consolidation of VIEs to certain entities in which the equity investors do not have the characteristics of a controlling financial interest or do not have sufficient equity at risk for the entity to finance its activities without additional subordinated financial support from other parties. Fixed price purchase and renewal options within a lease, as well as certain decision-making rights within a loan, can cause us to consider an entity a VIE. We previously determined that the developer entity of our consolidated Agrokor d.d. build-to-suit investment, referred to as Agrokor 4, was a VIE and that we were its primary beneficiary. During the six months ended June 30, 2015, in connection with the completion of the build-to-suit project, we acquired the shares of the developer entity and it is no longer a VIE. Additionally, we own interests in single-tenant, net-leased properties leased to companies through noncontrolling interests in partnerships and limited liability companies that we do not control, but over which we exercise significant influence. We account for these investments under the equity method of accounting. At times, the carrying value of our equity investments may fall below zero for certain investments. We intend to fund our share of the jointly-owned investments’ future operating deficits should the need arise. However, we have no legal obligation to pay for any of the liabilities of such investments nor do we have any legal obligation to fund operating deficits. At June 30, 2015, none of our equity investments had carrying values below zero.
Equity Method Investments	We own equity interests in net-leased properties that are generally leased to companies through noncontrolling interests (i) in partnerships and limited liability companies that we do not control but over which we exercise significant influence or (ii) as tenants-in-common subject to common control. Generally, the underlying investments are jointly-owned with affiliates. We account for these investments under the equity method of accounting. Earnings for each investment are recognized in accordance with each respective investment agreement and, where applicable, based upon an allocation of the investment’s net assets at book value as if the investment were hypothetically liquidated at the end of each reporting period. As required by current authoritative accounting guidance, we periodically compare an investment’s carrying value to its estimated fair value and recognize an impairment charge to the extent that the carrying value exceeds fair value and such decline is determined to be other than temporary. Additionally, we provide funding to developers for the acquisition, development, and construction of real estate, or ADC Arrangements. Under ADC Arrangements, we have provided two loans to third-party developers of real estate projects, which we account for as equity investments as the characteristics of the arrangement with the third-party developers are more similar to a jointly-owned investment or partnership rather than a loan.
Intangible Assets and Liabilities	Amortization of below-market rent and above-market rent intangibles is recorded as an adjustment to Rental income; amortization of below-market ground lease and above-market ground lease intangibles is included in Property expenses; and amortization of in-place lease and tenant relationship intangibles is included in Depreciation and amortization. In connection with our acquisitions of properties, we have recorded net lease intangibles that are being amortized over periods ranging from one year to 53 years. In addition, we have several ground lease intangibles that are being amortized over periods of up to 94 years. In-place lease intangibles and tenant relationship intangibles are included in In-place lease and tenant relationship intangible assets, net in the consolidated financial statements. Above-market rent, below-market ground lease (as lessee) intangibles, and goodwill are included in Other intangible assets, net in the consolidated financial statements. Below-market rent and above-market ground lease (as lessor) intangibles are included in Below-market rent and other intangible liabilities, net in the consolidated financial statements.
Fair Value of Financial Instruments	Derivative Assets — Our derivative assets, which are included in Other assets, net in the consolidated financial statements, are comprised of foreign currency forward contracts, stock warrants, embedded derivatives, and a swaption (Note 10). The foreign currency forward contracts and swaption were measured at fair value using readily observable market inputs, such as quotations on interest rates, and were classified as Level 2 as these instruments are custom, over-the-counter contracts with various bank counterparties that are not traded in an active market. The stock warrants and embedded derivatives were measured at fair value using internal valuation models that incorporated market inputs and our own assumptions about future cash flows. We classified these assets as Level 3 because they are not traded in an active market. Derivative Liabilities — Our derivative liabilities, which are included in Accounts payable, accrued expenses and other liabilities in the consolidated financial statements, are comprised of interest rate swaps and foreign currency forward contracts (Note 10). The interest rate swaps and foreign currency forward contracts were measured at fair value using readily observable market inputs, such as quotations on interest rates, and were classified as Level 2 because they are custom, over-the-counter contracts with various bank counterparties that are not traded in an active market. The fair value of an asset is defined as the exit price, which is the amount that would either be received when an asset is sold or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The guidance establishes a three-tier fair value hierarchy based on the inputs used in measuring fair value. These tiers are: Level 1, for which quoted market prices for identical instruments are available in active markets, such as money market funds, equity securities, and U.S. Treasury securities; Level 2, for which there are inputs other than quoted prices included within Level 1 that are observable for the instrument, such as certain derivative instruments including interest rate swaps and foreign currency forward contracts; and Level 3, for securities and other derivative assets that do not fall into Level 1 or Level 2 and for which little or no market data exists, therefore requiring us to develop our own assumptions.
Derivatives	We measure derivative instruments at fair value and record them as assets or liabilities, depending on our rights or obligations under the applicable derivative contract. Derivatives that are not designated as hedges must be adjusted to fair value through earnings. For a derivative designated, and that qualified, as a cash flow hedge, the effective portion of the change in fair value of the derivative is recognized in Other comprehensive income (loss) until the hedged item is recognized in earnings. For a derivative designated, and that qualified, as a net investment hedge, the effective portion of the change in the fair value and/or the net settlement of the derivative are reported in Other comprehensive income (loss) as part of the cumulative foreign currency translation adjustment. Amounts are reclassified out of Other comprehensive income (loss) into earnings when the hedged investment is either sold or substantially liquidated. The ineffective portion of the change in fair value of any derivative is immediately recognized in earnings.
Recent Accounting Requirements	The following Accounting Standards Updates, or ASUs, promulgated by the Financial Accounting Standards Board, are applicable to us: ASU 2015-03, Interest-Imputation of Interest (Subtopic 835-30) — ASU 2015-03 changes the presentation of debt issuance costs, which are currently recognized as a deferred charge (that is, an asset) and requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. ASU 2015-03 does not affect the recognition and measurement guidance for debt issuance costs. ASU 2015-03 is effective for periods beginning after December 15, 2015, early adoption is permitted and retrospective application is required. We are currently evaluating the impact of ASU 2015-03 on our consolidated financial statements. ASU 2014-09, Revenue from Contracts with Customers (Topic 606) — ASU 2014-09 is a comprehensive new revenue recognition model requiring a company to recognize revenue to depict the transfer of goods or services to a customer at an amount reflecting the consideration it expects to receive in exchange for those goods or services. ASU 2014-09 does not apply to our lease revenues, but will apply to reimbursed tenant costs and revenues generated from our operating properties. Additionally, this guidance modifies disclosures regarding the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. In April 2015, the Financial Accounting Standards Board issued a proposed ASU to defer the effective date of ASU 2014-09 by one year. In July 2015, the Financial Accounting Standards Board affirmed its proposal to defer the effective date of the new revenue standard for all entities by one year and directed the staff to draft a final ASU for vote by written ballot. Upon issuance of the final ASU deferring the effective date, ASU 2014-09 would be effective beginning in 2018, and early adoption is permitted but not before 2017, the original public company effective date. We are currently evaluating the impact of ASU 2014-09 on our consolidated financial statements and have not yet determined the method by which we will adopt the standard.

Disclosure of accounting policy for its derivative instruments and hedging activities.

- Definition

Disclosure of accounting policy for the equity method of accounting for investments in common stock or other interests including unconsolidated subsidiaries, corporate joint ventures, noncontrolling interests in real estate ventures, limited partnerships, and limited liability companies. The accounting policy may include information such as: (1) initially recording an investment in the stock of an investee at cost; (2) adjusting the carrying amount of the investment to recognize the investor's share of the earnings or losses of the investee after the date of acquisition; and (3) adjustments to reflect the investor's share of changes in the investee's capital (dividends). This disclosure may also include a detailed description of the policy for determining the amount of equity method losses recognized after an investment has been reduced to zero as a result of previous losses, reasons for not using the equity method when the investor company owns 20 percent or more of the voting stock of the investee's company (including identification of the significant investee), reasons for using the equity method when the ownership percentage is less than 20 percent, and discussion of recognition of equity method losses when an investor's total investment in an investee includes, in addition to an investment in common stock, other investments such as preferred stock and loans to the investee. An entity also may describe how such investments are assessed for impairment.

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