Income Taxes (Unaudited) (Tables)

6 Months Ended

Jun. 30, 2017

Income Tax Disclosure [Abstract]

Schedule of Income Tax Expense and Effective Income Tax Rates

	Three Months Ended June 30						Six Months Ended June 30
$ in millions	2017			2016			2017			2016
Federal and foreign income tax expense	$	255		$	213		$	388		$	333
Effective income tax rate	31.6		%	29.2		%	24.6		%	23.7		%