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DEBT - Additional Information (Detail)
1 Months Ended 12 Months Ended
Oct. 31, 2014
USD ($)
Sep. 30, 2014
USD ($)
Jul. 31, 2013
USD ($)
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Dec. 31, 2008
USD ($)
Dec. 31, 2014
USD ($)
Dec. 31, 2013
USD ($)
Debt Instrument [Line Items]                
Percentage of senior notes principal amount which may be redeemed at our option       100.00%        
Minimum level of net worth required       $ 9,000,000,000        
Actual net worth       10,685,000,000 $ 10,346,000,000   $ 9,646,000,000 $ 9,316,000,000
Uncommitted incremental loan facility       250,000,000        
Borrowings outstanding under credit agreement       0        
Outstanding letters of credit       0        
Remaining borrowing capacity       1,000,000,000        
Prior Credit Agreement                
Debt Instrument [Line Items]                
Revolving credit agreement term, in years     5 years          
Maximum borrowing capacity     $ 1,000,000,000.0          
Senior Notes                
Debt Instrument [Line Items]                
Net proceeds from debt   $ 1,730,000,000            
Reduction in unamortized value adjustment of senior notes       $ 23,000,000 $ 28,000,000 $ 103,000,000    
Senior Notes | $500 million, 6.45% due June 1, 2016                
Debt Instrument [Line Items]                
Debt redemption price, percentage 100.00%              
Early redemption of debt, amount $ 560,000,000              
Loss on extinguishment of debt 37,000,000              
Debt instrument, stated interest rate       6.45%        
Reduction in unamortized value adjustment of senior notes 12,000,000              
Principal amount redeemed $ 500,000,000              
Senior Notes | $500 million, 7.20% due June 15, 2018                
Debt Instrument [Line Items]                
Senior notes       $ 500,000,000        
Debt instrument, stated interest rate       7.20%        
Senior Notes | $250 million, 8.15% due June 15, 2038                
Debt Instrument [Line Items]                
Senior notes       $ 250,000,000        
Debt instrument, stated interest rate       8.15%        
Senior Notes | $300 million, 6.30% due August 1, 2018                
Debt Instrument [Line Items]                
Senior notes       $ 300,000,000        
Debt instrument, stated interest rate       6.30%        
Revolving Credit Facility | Line of Credit | Credit Agreement                
Debt Instrument [Line Items]                
Maximum leverage ratios for new credit agreement       3.0        
Actual net worth       $ 10,700,000,000        
Actual leverage ratio       1.4        
Revolving Credit Facility | Line of Credit | LIBOR | Credit Agreement                
Debt Instrument [Line Items]                
Basis points spread over LIBOR       1.00%        
Facility fee that is dependent upon credit rating, basis points       0.125%        
Revolving Credit Facility | Line of Credit | LIBOR | Credit Agreement | Minimum                
Debt Instrument [Line Items]                
Basis points spread over LIBOR       0.90%        
Facility fee that is dependent upon credit rating, basis points       0.10%        
Revolving Credit Facility | Line of Credit | LIBOR | Credit Agreement | Maximum                
Debt Instrument [Line Items]                
Basis points spread over LIBOR       1.50%        
Facility fee that is dependent upon credit rating, basis points       25.00%