Impairments	12 Months Ended
Dec. 31, 2017
Asset Impairment Charges [Abstract]
Impairments	Impairments Casualty-Related As a result of Hurricane Harvey and Hurricane Irma during the year ended December 31, 2017, the Company recorded an estimated $13 million of casualty-related losses, net of a small insurance recovery. The losses are comprised of $8 million of property damage and $5 million of other associated costs, including storm preparation, clean up, relocation and other costs. Of the total $13 million casualty losses incurred, $12 million was recorded in Other income (expense), net, and $1 million was recorded in equity income (loss) from unconsolidated joint ventures as it relates to casualty losses for properties owned by certain of our unconsolidated joint ventures. In addition, the Company recorded a $1 million deferred tax benefit associated with the casualty-related losses. Real Estate During the third quarter 2017, the Company determined that 11 underperforming senior housing triple-net assets that are candidates for potential future sale were impaired. Accordingly, the Company wrote-down the carrying amount of these 11 assets to their fair value, which resulted in an aggregate impairment charge of $23 million. The fair value of the assets was based on forecasted sales prices which are considered to be Level 2 measurements within the fair value hierarchy. Other See Note 7 for further information on the impairment charges related to the mezzanine loan facility to Tandem (the "Tandem Mezzanine Loan"). In June 2015 and September 2015, the Company determined that its Four Seasons senior notes (the “Four Seasons Notes”) were other-than-temporarily impaired resulting from a continued decrease in the fair value of its investment. Although the Company did not intend to sell and did not believe it would be required to sell the Four Seasons Notes before their maturity, the Company determined that a credit loss existed resulting from several factors including: (i) deterioration in Four Seasons’ operating performance since the fourth quarter of 2014 and (ii) credit downgrades to Four Seasons received during the first half of 2015. Accordingly, the Company recorded impairment charges during the three months ended June 30, 2015 and September 30, 2015 of $42 million and $70 million, respectively, reducing the carrying value of the Four Seasons Notes at September 30, 2015 to $100 million (£66 million). The fair value of the Four Seasons Notes used to calculate the impairment charge was based on quoted market prices. However, because the Four Seasons Notes were not actively traded, these prices were considered to be Level 2 measurements within the fair value hierarchy. When calculating the fair value and determining whether a credit loss existed, the Company also evaluated Four Season’s ability to repay the Four Seasons Notes according to their contractual terms based on its estimate of future cash flows. The estimated future cash flow inputs included forecasted revenues, capital expenditures, operating expenses, care home occupancy and continued implementation of Four Seasons’ business plan which included executing on its business line segmentation and continuing to invest in its core real estate portfolio. This information was consistent with the results of the valuation technique used by the Company to determine if a credit loss existed and to calculate the fair value of the Four Seasons Notes during its impairment review. In March 2017, pursuant to a shift in the Company’s investment strategy, the Company sold its £138.5 million par value Four Seasons Notes for £83 million ($101 million). The disposition of the Four Seasons Notes generated a £42 million ($51 million) gain on sale, recognized in other income, net, as the sales price was above the previously-impaired carrying value of £41 million ($50 million). Through October 2015, the Company held a secured term loan made to Delphis Operations, L.P. (“Delphis”). In October 2015, the Company received $23 million in cash proceeds from the sale of Delphis’ collateral and recognized an impairment recovery of $6 million for the amount received in excess of the loan’s carrying value.

Impairments

Casualty-Related

As a result of Hurricane Harvey and Hurricane Irma during the year ended December 31, 2017, the Company recorded an estimated $13 million of casualty-related losses, net of a small insurance recovery. The losses are comprised of $8 million of property damage and $5 million of other associated costs, including storm preparation, clean up, relocation and other costs. Of the total $13 million casualty losses incurred, $12 million was recorded in Other income (expense), net, and $1 million was recorded in equity income (loss) from unconsolidated joint ventures as it relates to casualty losses for properties owned by certain of our unconsolidated joint ventures. In addition, the Company recorded a $1 million deferred tax benefit associated with the casualty-related losses.

Real Estate

During the third quarter 2017, the Company determined that 11 underperforming senior housing triple-net assets that are candidates for potential future sale were impaired. Accordingly, the Company wrote-down the carrying amount of these 11 assets to their fair value, which resulted in an aggregate impairment charge of $23 million. The fair value of the assets was based on forecasted sales prices which are considered to be Level 2 measurements within the fair value hierarchy.

Other

See Note 7 for further information on the impairment charges related to the mezzanine loan facility to Tandem (the "Tandem Mezzanine Loan").

In June 2015 and September 2015, the Company determined that its Four Seasons senior notes (the “Four Seasons Notes”) were other-than-temporarily impaired resulting from a continued decrease in the fair value of its investment. Although the Company did not intend to sell and did not believe it would be required to sell the Four Seasons Notes before their maturity, the Company determined that a credit loss existed resulting from several factors including: (i) deterioration in Four Seasons’ operating performance since the fourth quarter of 2014 and (ii) credit downgrades to Four Seasons received during the first half of 2015. Accordingly, the Company recorded impairment charges during the three months ended June 30, 2015 and September 30, 2015 of $42 million and $70 million, respectively, reducing the carrying value of the Four Seasons Notes at September 30, 2015 to $100 million (£66 million).

The fair value of the Four Seasons Notes used to calculate the impairment charge was based on quoted market prices. However, because the Four Seasons Notes were not actively traded, these prices were considered to be Level 2 measurements within the fair value hierarchy. When calculating the fair value and determining whether a credit loss existed, the Company also evaluated Four Season’s ability to repay the Four Seasons Notes according to their contractual terms based on its estimate of future cash flows. The estimated future cash flow inputs included forecasted revenues, capital expenditures, operating expenses, care home occupancy and continued implementation of Four Seasons’ business plan which included executing on its business line segmentation and continuing to invest in its core real estate portfolio. This information was consistent with the results of the valuation technique used by the Company to determine if a credit loss existed and to calculate the fair value of the Four Seasons Notes during its impairment review.

In March 2017, pursuant to a shift in the Company’s investment strategy, the Company sold its £138.5 million par value Four Seasons Notes for £83 million ($101 million). The disposition of the Four Seasons Notes generated a £42 million ($51 million) gain on sale, recognized in other income, net, as the sales price was above the previously-impaired carrying value of £41 million ($50 million).

Through October 2015, the Company held a secured term loan made to Delphis Operations, L.P. (“Delphis”). In October 2015, the Company received $23 million in cash proceeds from the sale of Delphis’ collateral and recognized an impairment recovery of $6 million for the amount received in excess of the loan’s carrying value.