Consolidated Statement of Shareholders' Equity (unaudited) - USD ($) $ in Millions	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income [Member]	Deferred Equity Compensation [Member]
Beginning balance at Dec. 31, 2014					$ 370
Increase (Decrease) in Shareholders' Equity
Net Income	$ 498
Other comprehensive income	(131)
Ending balance at Jun. 30, 2015					239
Beginning balance at Mar. 31, 2015					370
Increase (Decrease) in Shareholders' Equity
Net Income	297
Other comprehensive income	(131)
Ending balance at Jun. 30, 2015					239
Beginning balance (in shares) at Dec. 31, 2015		137,928,552
Beginning balance at Dec. 31, 2015	6,063	$ 1	$ 1,342	$ 4,478	237	$ 5
Increase (Decrease) in Shareholders' Equity
Net Income	205			205
Dividends ($0.26 per share)	(35)			(35)
Common stock repurchases (in shares)		(5,370,402)
Common stock repurchases	(135)		(135)
Share-based compensation and other (in shares)		256,272
Share-based compensation and other	6		6
Other comprehensive income	146				146
Ending balance (in shares) at Jun. 30, 2016		132,814,422
Ending balance at Jun. 30, 2016	6,250	$ 1	1,213	4,648	383	5
Beginning balance at Mar. 31, 2016					319
Increase (Decrease) in Shareholders' Equity
Net Income	146
Other comprehensive income	64
Ending balance (in shares) at Jun. 30, 2016		132,814,422
Ending balance at Jun. 30, 2016	$ 6,250	$ 1	$ 1,213	$ 4,648	$ 383	$ 5