Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2017

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

Schedule Of Stock-Based Compensation Expense

Pretax stock-based compensation costs, the tax benefit associated with stock-based compensation expense and stock-based compensation costs capitalized are included in the following table.

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
(in millions)	2017		2016		2017		2016
Restricted stock unit awards	$	10	$	8	$	30	$	25
Performance awards	7		4		20		14
Pretax stock-based compensation cost	$	17	$	12	$	50	$	39
Tax benefit associated with stock-based compensation expense	$	6	$	5	$	18	$	14
Stock-based compensation costs capitalized	1		—		2		2