Quarterly report pursuant to Section 13 or 15(d)

New Accounting Pronouncements (Narrative) (Details)

v3.10.0.1
New Accounting Pronouncements (Narrative) (Details) - USD ($)
$ in Millions
Jun. 30, 2018
Dec. 31, 2017
Jun. 30, 2017
Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Cumulative effect of change in accounting standard   $ (15)    
Total cash, cash equivalents and restricted cash $ 416 59 $ 35 $ 30
Cash and cash equivalents 416 57    
Other current assets        
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Restricted cash $ 0 2    
Accounting Standards Update 2014-09 | New Revenue Standard Adjustment | Retained Earnings        
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Cumulative effect of change in accounting standard       $ (29)
Accounting Standards Update 2016-16 | Retained Earnings        
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Cumulative effect of change in accounting standard   $ 15