Employee Benefit Plans - Fair Values of Company's Pension Plan Assets (Detail) (USD $)
In Millions, unless otherwise specified
Dec. 31, 2013
Dec. 31, 2012
Pension Plans, Postretirement and Other Employee Benefits [Line Items]    
Total $ 523 $ 497
Common and Commingled Trust Funds [Member]
    
Pension Plans, Postretirement and Other Employee Benefits [Line Items]    
Total 414 438
Mutual Funds [Member]
    
Pension Plans, Postretirement and Other Employee Benefits [Line Items]    
Total 98 47
Cash Equivalents [Member]
    
Pension Plans, Postretirement and Other Employee Benefits [Line Items]    
Total 11 12
Level 1 [Member]
    
Pension Plans, Postretirement and Other Employee Benefits [Line Items]    
Total 109 59
Level 1 [Member] | Common and Commingled Trust Funds [Member]
    
Pension Plans, Postretirement and Other Employee Benefits [Line Items]    
Total      
Level 1 [Member] | Mutual Funds [Member]
    
Pension Plans, Postretirement and Other Employee Benefits [Line Items]    
Total 98 47
Level 1 [Member] | Cash Equivalents [Member]
    
Pension Plans, Postretirement and Other Employee Benefits [Line Items]    
Total 11 12
Level 2 [Member]
    
Pension Plans, Postretirement and Other Employee Benefits [Line Items]    
Total 414 438
Level 2 [Member] | Common and Commingled Trust Funds [Member]
    
Pension Plans, Postretirement and Other Employee Benefits [Line Items]    
Total 414 438
Level 2 [Member] | Mutual Funds [Member]
    
Pension Plans, Postretirement and Other Employee Benefits [Line Items]    
Total      
Level 2 [Member] | Cash Equivalents [Member]
    
Pension Plans, Postretirement and Other Employee Benefits [Line Items]    
Total