v3.10.0.1
Debt - Additional Information (Detail) - USD ($)
$ / shares in Units, shares in Thousands
12 Months Ended
Sep. 19, 2018
Dec. 31, 2018
Dec. 31, 2017
Dec. 06, 2018
Mar. 08, 2018
Mar. 02, 2018
Jan. 01, 2016
Nov. 30, 2014
Debt Instrument [Line Items]                
Book value of outstanding long-term debt   $ 6,247,000,000 $ 5,814,000,000          
Debt issuance costs   32,000,000            
Debt discount   $ 3,000,000            
Remaining tenor of debt   3 years 9 months 18 days            
Interest accrued for debt   $ 31,000,000 35,000,000          
Principal amount of debt   7,400,000,000 6,650,000,000          
Portion of principal amount of long-term and short-term debt, secured by collateral   $ 0 0          
Debt instrument, interest rate   0.00%            
Debt instrument trading price, percentage   98.00%            
Warrant [Member]                
Debt Instrument [Line Items]                
Issue of warrants to purchase shares of common stock   11,180            
Exercise price   $ 133.32            
Warrants expiration date   Mar. 02, 2020            
Cash proceeds from the sale of the warrants   $ 134,000,000            
Carrying value of the warrants             $ 168,000,000  
Minimum [Member]                
Debt Instrument [Line Items]                
Common stock exchange percentage threshold   50.00%            
Percentage of consideration received by share holders   90.00%            
Secured Debt [Member]                
Debt Instrument [Line Items]                
Remaining tenor of debt   3 years 9 months 18 days            
2019 Cash Convertible Senior Notes [Member]                
Debt Instrument [Line Items]                
Principal amount of debt   $ 1,150,000,000 1,150,000,000         $ 1,150,000,000
Debt instrument, interest rate               1.00%
Notes maturity date   Dec. 01, 2019            
Fees and expenses capitalized as deferred financing costs   $ 16,000,000            
Debt instrument, frequency of periodic payment   Semi-annually each December 1st and June 1st.            
Debt instrument trading price, percentage   130.00%            
Initial cash conversion rate, shares   9.7236            
Initial cash conversion price, debt   $ 1,000            
Cash conversion price   $ 102.84            
Minimum principal amount on fundamental change repurchase date   $ 200,000            
Cash Convertible Senior Notes, Description   If a “fundamental change” (as defined below in this section) occurs at any time, holders will have the right, at their option, to require us to repurchase for cash all of their 2019 Cash Convertible Senior Notes, or any portion of the principal thereof that is equal to $1,000 or a multiple of $1,000 (provided that the portion of any global note or certified note, as applicable, not tendered for repurchase has a principal amount of at least $200,000, on the fundamental change repurchase date.            
Fair value of Cash Convertible Senior Notes   $ 1,327,000,000            
2019 Cash Convertible Senior Notes [Member] | Level III [Member]                
Debt Instrument [Line Items]                
Fair value of notes   24,000,000 301,000,000          
Profit (loss) on embedded cash conversion option   277,000,000 (43,000,000)          
Notes Hedges [Member]                
Debt Instrument [Line Items]                
Aggregate cost of the Notes Hedges   208,000,000            
Estimated fair value of the Notes Hedges   24,000,000 301,000,000          
Variable Interest Rate Indebtedness under Loan Agreements [Member]                
Debt Instrument [Line Items]                
Aggregate principal amount of variable interest rate indebtedness   $ 0            
Senior Unsecured Notes Due 2024 [Member]                
Debt Instrument [Line Items]                
Principal amount of debt       $ 1,000,000,000        
Fixed rate on notes       4.875%        
Senior Unsecured Notes Due 2026 [Member]                
Debt Instrument [Line Items]                
Principal amount of debt       $ 500,000,000        
Fixed rate on notes       5.35%        
Senior Unsecured Notes Due 2028 [Member]                
Debt Instrument [Line Items]                
Principal amount of debt       $ 500,000,000        
Fixed rate on notes       5.55%        
2019 Bridge Loan [Member]                
Debt Instrument [Line Items]                
Principal amount of debt $ 1,000,000,000              
Debt instrument maturity date description   The Bridge Loan was to mature 364 days following the closing date of September 19, 2018            
2019 Bridge Loan [Member] | LIBOR [Member]                
Debt Instrument [Line Items]                
Debt instrument applicable margin rate 1.50%              
2019 Bridge Loan [Member] | Senior Unsecured Bridge Term Credit Facility [Member]                
Debt Instrument [Line Items]                
Amount of credit facility $ 1,000,000,000              
Senior Notes Due 2018 [Member]                
Debt Instrument [Line Items]                
Principal amount of debt         $ 750,000,000      
Fixed rate on notes         3.75%      
Senior Notes Due 2023 [Member]                
Debt Instrument [Line Items]                
Principal amount of debt           $ 500,000,000    
Fixed rate on notes           5.75%    
Dollar Denominated Revolving Credit Facilities [Member]                
Debt Instrument [Line Items]                
Amount of credit facility   $ 600,000,000 $ 600,000,000