Pensions and Other Employee Benefits - Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Pension Plans [Member]
Other changes in plan assets and benefit obligations recognized in other comprehensive income:
Net loss (gain)	$ 287	$ 266	$ 234
Prior service (credit) cost	(1)	2	(33)
Amortization of net loss	(69)	(49)	(40)
Amortization of prior service (cost) credit	(1)	(1)	(3)
Total recognized in other comprehensive income	216	218	158
Total recognized in net periodic benefit cost and other comprehensive income	395	363	312
Postretirement Benefit Plans [Member]
Other changes in plan assets and benefit obligations recognized in other comprehensive income:
Net loss (gain)	(3)	10	8
Prior service (credit) cost	(5)		2
Amortization of net loss	(1)	(1)	(1)
Amortization of prior service (cost) credit	3	3	3
Total recognized in other comprehensive income	(6)	12	12
Total recognized in net periodic benefit cost and other comprehensive income	$ 4	$ 23	$ 21