XML 56 R42.htm IDEA: XBRL DOCUMENT v3.19.2
Long-Term Debt - Additional Information (Detail) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Mar. 31, 2019
Jun. 30, 2019
Jun. 30, 2018
Debt Disclosure [Abstract]      
Interest paid, net of amounts capitalized   $ 176 $ 144
Maximum borrowing capacity under credit facility   4,500  
Senior Notes | Series BB Notes      
Debt Instrument [Line Items]      
Senior notes, face amount $ 300 300  
Senior Notes | Series CC Notes      
Debt Instrument [Line Items]      
Senior notes, face amount $ 550 $ 550  
Interest rate 3.60% 3.60%  
Senior Notes | Series BB and Series CC Notes      
Debt Instrument [Line Items]      
Proceeds from debt offering $ 841    
LIBOR | Senior Notes | Series BB Notes      
Debt Instrument [Line Items]      
Variable interest rate 0.65%