XML 123 R103.htm IDEA: XBRL DOCUMENT v3.3.1.900
Long-Term Debt - Additional Information (Detail) - USD ($)
$ in Millions
Dec. 31, 2015
Dec. 31, 2014
Debt Instrument [Line Items]    
Notes and debentures that mature in 2016 $ 2,450  
Notes and debentures that mature in 2017 1,250  
Notes and debentures that mature in 2018 3,650  
Notes and debentures that mature in 2019 4,250  
Notes and debentures that mature in 2020 4,010  
Carrying value [1] 2,552 $ 1,562
Series A Preferred Stock    
Debt Instrument [Line Items]    
Carrying value $ 500 $ 500
[1] .