Income Taxes (Unaudited) (Tables)

3 Months Ended

Mar. 31, 2018

Income Tax Disclosure [Abstract]

Schedule of Income Tax Expense and Effective Income Tax Rates

	Three Months Ended March 31
$ in millions	2018			2017
Federal and foreign income tax expense	$	132		$	138
Effective income tax rate	15.2		%	17.5		%