v2.4.0.8
Pension and Other Postretirement Benefit Plans - Summary of Changes in Fair Value of Company's Level 3 Pension Plan Assets (Detail) (Significant Unobservable Inputs (Level 3) [Member], USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]    
Fair value of plan assets January 1 $ 692 $ 637
Relating to assets still held at December 31 31 53
Relating to assets sold during the year 3 (6)
Purchases 21 25
Sales (31) (26)
Transfers (out of) into Level 3 (94) 9
Fair value of plan assets December 31 622 692
Insurance Contracts [Member]
   
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]    
Fair value of plan assets January 1 496 428
Relating to assets still held at December 31 30 35
Relating to assets sold during the year 1 1
Purchases 18 21
Sales (2) (11)
Transfers (out of) into Level 3 (3) 22
Fair value of plan assets December 31 540 496
Real Estate [Member]
   
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]    
Fair value of plan assets January 1 141 144
Relating to assets still held at December 31 0 20
Relating to assets sold during the year (1) (12)
Purchases 0 0
Sales 0 (1)
Transfers (out of) into Level 3 (91) (10)
Fair value of plan assets December 31 49 141
Other Investment [Member]
   
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]    
Fair value of plan assets January 1 55 65
Relating to assets still held at December 31 1 (2)
Relating to assets sold during the year 3 5
Purchases 3 4
Sales (29) (14)
Transfers (out of) into Level 3 0 (3)
Fair value of plan assets December 31 $ 33 $ 55