Common Share Repurchases (details) (Board of Directors Approved Repurchase Authorizations [Member], USD $) Share data in Millions, except Per Share data, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014
Board of Directors Approved Repurchase Authorizations [Member]
Repurchase activity
Number of shares repurchased (in shares)	8.1	25.4
Cost of shares repurchased	$ 750,000,000	$ 2,280,000,000
Average cost per share repurchased	$ 92.47	$ 89.61
Remaining capacity under share repurchase authorization	$ 2,480,000,000	$ 2,480,000,000