Share-Based Compensation Plans - Summary of the status of the Company's share options and related information (Details) - Share options [Member] - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share Options
Outstanding at beginning of period (in shares)	2,300	3,462	5,611
Granted (in shares)	0	0	0
Exercised (in shares)	(1,450)	(1,155)	(2,116)
Forfeited and expired (in shares)	(13)	(7)	(33)
Outstanding at end of period (in shares)	837	2,300	3,462
Exercisable at end of period (in shares)	837	2,273	3,270
Shares available for grant (in shares)	12,179	16,333	11,330
Weighted-Average Exercise Price
Outstanding at beginning of period (in dollars per share)	$ 32	$ 32	$ 32
Granted (in dollars per share)	0	0	0
Exercised (in dollars per share)	27	33	32
Forfeited and expired (in dollars per share)	39	37	34
Outstanding at end of period (in dollars per share)	40	32	32
Exercisable at end of period (in dollars per share)	$ 40	$ 32	$ 32