Income Taxes - Provision for Income Taxes (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Current:
Federal	$ 414us-gaap_CurrentFederalTaxExpenseBenefit	$ 389us-gaap_CurrentFederalTaxExpenseBenefit	$ 268us-gaap_CurrentFederalTaxExpenseBenefit
State	61	79	72
Foreign	56us-gaap_CurrentForeignTaxExpenseBenefit	45us-gaap_CurrentForeignTaxExpenseBenefit	36us-gaap_CurrentForeignTaxExpenseBenefit
Current total	531us-gaap_CurrentIncomeTaxExpenseBenefit	513us-gaap_CurrentIncomeTaxExpenseBenefit	376us-gaap_CurrentIncomeTaxExpenseBenefit
Deferred:
Federal	(89)	(82)	48
State	(33)	(14)	17
Foreign	4	(53)	2
Deferred total	(118)us-gaap_DeferredIncomeTaxExpenseBenefit	(149)us-gaap_DeferredIncomeTaxExpenseBenefit	67us-gaap_DeferredIncomeTaxExpenseBenefit
Provision for income taxes	$ 413us-gaap_IncomeTaxExpenseBenefit	$ 364us-gaap_IncomeTaxExpenseBenefit	$ 443us-gaap_IncomeTaxExpenseBenefit

Amount of current federal tax expense (benefit) pertaining to income (loss) from continuing operations.

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