Employee Related Benefits - Net Pension Amounts Recognized in the Consolidated Balance Sheets (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Pension Benefit Costs [Member]
Defined Benefit Plan Disclosure [Line Items]
Accrued employee benefit liability	$ 224	$ 77
Accumulated other comprehensive income (loss):
Net actuarial gain (loss)	(439)	(282)
Prior service credit (cost)	71	79
Accumulated other comprehensive income (loss) before tax	(368)	(203)
Less: Income taxes	129	71
Accumulated other comprehensive income (loss)	(239)	(132)
Other Benefit Costs [Member]
Defined Benefit Plan Disclosure [Line Items]
Accrued employee benefit liability	149	117
Accumulated other comprehensive income (loss):
Net actuarial gain (loss)	(16)	10
Prior service credit (cost)	2	3
Accumulated other comprehensive income (loss) before tax	(14)	13
Less: Income taxes	5	(5)
Accumulated other comprehensive income (loss)	$ (9)	$ 8