Employee Benefit Plans and Postretirement Benefits - Pre-tax Amounts Expected to be Amortized from Accumulated Other Comprehensive Income (Loss) (Detail) $ in Millions	12 Months Ended
Dec. 31, 2015 USD ($)
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Actuarial losses	$ (79)
Total	(79)
Healthcare [Member]
Defined Benefit Plan Disclosure [Line Items]
Actuarial losses	(15)
Prior service (cost) credit	4
Total	(11)
Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Prior service (cost) credit	(1)
Total	$ (1)

Amount included in accumulated other comprehensive income (AOCI) expected to be recognized as components of net periodic benefit cost for the fiscal year that follows the most recent annual statement of financial position, including gain (loss), prior service cost (credit), and transition asset (obligation).

No definition available.

Name:	us-gaap_DefinedBenefitPlanAmountToBeAmortizedFromAccumulatedOtherComprehensiveIncomeLossNextFiscalYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration