Employee Pension and Other Benefit Plans - Employee Pension and Other Benefit Plans (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Pension Benefit Costs [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 6	$ 9	$ 19	$ 27
Interest cost	10	11	30	31
Expected return on plan assets	(12)	(12)	(38)	(37)
Amortization, net	3	8	10	26
Settlements	3	5	6	5
Benefit costs, net	10	21	27	52
Other Benefit Costs [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	2	3
Interest cost	2	1	5	4
Benefit costs, net	$ 3	$ 2	$ 7	$ 7