Earnings Per Share, Share Repurchases and Dividends on Common Stock (Tables)

12 Months Ended

Dec. 31, 2015

Earnings Per Share [Abstract]

Share Repurchases

The table below summarizes the company’s share repurchases:

Repurchase Program Authorization Date	Amount Authorized (in millions)		Total Shares Retired (in millions)	Average  Price Per Share(1)		Date Completed	Shares Repurchased (in millions)
							Year Ended December 31
							2015	2014	2013
June 16, 2010	$	5,350	83.7	$	63.86	September 2013	—	—	18.6
May 15, 2013	$	4,000	32.8	$	121.97	March 2015	2.7	21.4	8.7
December 4, 2014	$	3,000	16.6	$	164.72		16.6	—	—
September 16, 2015	$	4,000	—	$	—		—	—	—
							19.3	21.4	27.3

⁽¹⁾  Includes commissions paid.