v3.8.0.1
Health Net - Schedule of Recognized Identifiable Assets Acquired and Liabilities Assumed (Details) - USD ($)
$ in Millions
 12 Months Ended
Mar. 24, 2016
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Business Acquisition [Line Items]        
Goodwill   $ 4,749 $ 4,712 $ 842
Managed Care        
Business Acquisition [Line Items]        
Goodwill   4,015 4,015 361
Specialty Services        
Business Acquisition [Line Items]        
Goodwill   $ 734 $ 697 $ 481
Health Net, Inc.        
Business Acquisition [Line Items]        
Cash and cash equivalents $ 956      
Premium and trade receivables 1,890      
Short-term investments 74      
Other current assets 524      
Long-term investments 2,037      
Restricted deposits 30      
Property, software and equipment, net 41      
Intangible assets 1,530      
Other long-term assets 136      
Total assets acquired 7,218      
Medical claims liability 1,482      
Borrowings under revolving credit facility 285      
Accounts payable and accrued expenses 2,297      
Return of premium payable 435      
Unearned revenue 130      
Long-term deferred tax liabilities 311      
Long-term debt 418      
Other long-term liabilities 432      
Total liabilities assumed 5,790      
Total identifiable net assets 1,428      
Goodwill 3,859      
Total assets acquired and liabilities assumed 5,287      
Estimated fair value of risk corridor receivable $ 9      
Acquired finite-lived intangible assets, weighted average useful life 12 years 12 years    
Substance abuse rehabilitation claims recorded in medical claims liability $ 160      
Premium deficiency reserves 253      
Deferred tax liabilities noncurrent, net 365      
Health Net, Inc. | Managed Care        
Business Acquisition [Line Items]        
Goodwill 3,643      
Health Net, Inc. | Specialty Services        
Business Acquisition [Line Items]        
Goodwill 216      
Health Net, Inc. | Total senior notes        
Business Acquisition [Line Items]        
Long-term debt 418      
Face amount of senior notes 400      
Unamortized premium $ 18