EPS (Calculation of Earnings Per Share and the Reconciliation of Earnings Per Sahre to Earnings Per Diluted Share) (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2016	Jun. 30, 2016
Earnings Per Share [Abstract]
Net tax deficiency reclassified from capital surplus to applicable income tax expense	$ 5	$ 6

Amount of increase (decrease) in additional paid in capital (APIC) resulting from a tax benefit (deficiency) associated with an share-based compensation plan other than an employee stock ownership plan (ESOP).

No definition available.

Name:	us-gaap_AdjustmentToAdditionalPaidInCapitalIncomeTaxEffectFromShareBasedCompensationNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration