Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2015

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

Details of Grants of Stock-based Compensation

The following are the details of grants of stock-based compensation during the six months ended June 30, 2015 and 2014:

	Six Months Ended June 30
	2015			2014
Grant Details	Shares	Fair Value		Shares	Fair Value
Stock options	583,172	$	26.98	716,102	$	21.53
Restricted stock units	193,990	$	114.02	253,492	$	90.19
Contingent shares (a)	63,308	$	118.12	77,642	$	93.53

(a) The number of contingent shares represents the target value of the award.

	Three Months Ended June 30				Six Months Ended June 30
($ in millions)	2015		2014		2015		2014
Total stock-based compensation	$	25	$	20	$	40	$	38
Income tax benefit recognized	$	9	$	7	$	14	$	13

Weighted Average Assumptions Used in Calculating the Fair Value of Stock Option

The fair value of the stock option grants issued in the six months ended June 30, 2015 was calculated with the following weighted average assumptions:

Weighted average exercise price	$	118.12
Risk-free interest rate	1.9		%
Expected life of option in years	6.5
Expected dividend yield	2.7		%
Expected volatility	29.2		%