Share-Based Compensation Plans (Tables)

3 Months Ended

Mar. 31, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Amounts of Share-Based Compensation Cost Recorded in Consolidated Statement of Income

The following table provides the amounts of share-based compensation cost recorded in the Condensed Consolidated Statement of Income:



	Three Months Ended March 31,
($ in millions)	2018			2017
Pretax share-based compensation expense	$	80		$	74
Income tax benefit	(15		)	(22		)
Total share-based compensation expense, net of taxes	$	65		$	52

Assumptions Used to Determine Weighted-Average Fair Value of Options Granted

The weighted-average fair value of options granted for the first three months of 2018 and 2017 was $7.83 and $7.89 per option, respectively, and was determined using the following assumptions:



	Three Months Ended March 31,
	2018		2017
Expected dividend yield	3.4	%	3.7	%
Risk-free interest rate	2.7	%	2.0	%
Expected volatility	19.5	%	19.7	%
Expected life (years)	6.0		6.2