Income Taxes (Unaudited) (Tables)

9 Months Ended

Sep. 30, 2012

Income Tax Disclosure [Abstract]

Schedule of Income Tax Expense and Effective Income Tax Rates

	Three Months Ended September 30				Nine Months Ended September 30
$ in millions	2012		2011		2012		2011
Federal and foreign income tax expense	236		235		733		765
Effective income tax rate	34.0	%	31.1	%	33.7	%	33.2	%