Income Taxes - Additional Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Income Taxes Other Information [Line Items]
Income Tax Expense (Benefit)	$ 146	$ 91	$ 297	$ 160
Effective Income Tax Rate, Continuing Operations	28.00%	25.00%	29.00%	23.00%
Income Tax, Policy [Policy Text Block]			The Company calculated the provision for income taxes for the three and six months ended June 30, 2013, by applying the estimated annual effective tax rate to year-to-date pre-tax income. For the three and six months ended June 30, 2012, the provision for income taxes was calculated discretely based on actual year-to-date results. Interest and penalties related to tax matters are recorded as a component of the income tax provision.