Share-Based Compensation Plans - Restricted share unit activity (Details) - Restricted share units (RSUs) [Member] - $ / shares shares in Thousands		9 Months Ended		12 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Non-vested share awards (in shares)
Non-vested at beginning of period		8,381	9,759	9,759
Granted		2,298	2,675
Vested		(3,217)	(3,561)
Forfeited		(228)	(385)
Non-vested at end of period		7,234	8,488	8,381
Weighted Average Fair value (in dollars per share)
Non-vested at beginning of period	[1]	$ 63	$ 51	$ 51
Granted	[1]	98	84
Vested	[1]	58	49
Forfeited	[1]	70	56
Non-vested at end of period	[1]	$ 77	$ 63	$ 63

[1] Represents per share weighted average fair value of award at date of grant.