Income Taxes - Additional information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended				12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2010 Maximum [Member]	Dec. 31, 2012 Federal [Member]	Dec. 31, 2012 Total Foreign [Member]	Dec. 31, 2012 State [Member]
Income Taxes [Line Items]
Capital loss carry forwards	$ 20
Deferred tax asset related to capital loss	7
Net operating loss carry forwards						6	22	118
Valuation allowance against deferred tax asset	9
Tax credit carry forwards	9
Expected state net operating losses to be utilized	71
Unrecognized tax benefits	130	143	195	185
Unrecognized tax benefits that would reduce the effective income tax rate	70
Anticipated decrease in unrecognized tax benefit over the next 12 months	20
Change in previously accrued income tax expenses related to tax returns	10	81
Change in previously accrued income tax expenses related to audit		12
Accrued potential interest included with in current and non current income taxes payable	11	11
Accrued potential interest included within current and non current income taxes payable after income taxes	6	7
Potential penalties	7	8
Expense (benefit) for Interest related items included in income tax expenses	2	6			1
Undistributed earnings of non us companies	$ 346