v3.19.3
Variable Interest Entities ("VIEs") - Narrative (Details)
1 Months Ended 3 Months Ended 9 Months Ended
Jul. 02, 2019
Apr. 30, 2019
Mar. 31, 2018
USD ($)
Sep. 30, 2019
USD ($)
Sep. 30, 2018
USD ($)
Sep. 30, 2019
USD ($)
Sep. 30, 2018
USD ($)
Dec. 31, 2018
USD ($)
Jun. 30, 2018
building
subsidiary
Variable Interest Entity [Line Items]                  
Equity method investments       $ 1,393,000,000   $ 1,393,000,000   $ 1,312,000,000  
Limited guarantee       50,000,000   50,000,000   50,000,000  
Loss from equity method investment, net of tax       (9,000,000) $ (15,000,000) (25,000,000) $ (32,000,000)    
Event Center Office Partners, LLC                  
Variable Interest Entity [Line Items]                  
Impairment of equity method investments           0      
Variable Interest Entity, Primary Beneficiary                  
Variable Interest Entity [Line Items]                  
Percentage of ownership before sale of stock   100.00%              
Assets       1,300,000,000   1,300,000,000   115,000,000  
Liabilities       173,000,000   173,000,000   $ 0  
Variable Interest Entity, Not Primary Beneficiary                  
Variable Interest Entity [Line Items]                  
Number of office buildings managed | building                 2
Number of wholly owned subsidiaries owning buildings | subsidiary                 2
Variable Interest Entity, Not Primary Beneficiary | Event Center Office Partners, LLC                  
Variable Interest Entity [Line Items]                  
Ownership interest     45.00%            
Payments to acquire variable interest entity     $ 136,000,000            
Equity method investments       136,000,000   136,000,000      
Limited guarantee       $ 50,000,000   $ 50,000,000      
Variable Interest Entity, Not Primary Beneficiary | LLC Partner One | Event Center Office Partners, LLC                  
Variable Interest Entity [Line Items]                  
Ownership interest     45.00%            
Variable Interest Entity, Not Primary Beneficiary | LLC Partner Two | Event Center Office Partners, LLC                  
Variable Interest Entity [Line Items]                  
Ownership interest     10.00%            
Preferred Class A | Softbank, Toyota, and DENSO | ATG Investment                  
Variable Interest Entity [Line Items]                  
Sale of stock, percentage of ownership after transaction 13.80%