Income Taxes (Unaudited) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Income Tax Contingency [Line Items]
Income Tax Expense (Benefit)	$ 245	$ 236	$ 452	$ 459
Effective income tax rate	32.40%	32.60%	29.30%	32.00%
Income Tax Expense Benefit, Period Increase (Decrease) due to tax settlement			(51)
Unrecognized Tax Benefits, Period Increase (Decrease) due to tax settlement			(59)
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	$ 12		$ 12