CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Common shares, par value (in dollars per share)	$ 0.01	$ 0.01
Common shares, shares authorized	1,250,000,000	1,250,000,000
Common shares, shares issued	322,742,143	320,990,255
Treasury shares	147,720,668	137,880,746
Consolidated investment entities [Member]
Receivables, fair value (in dollars)	$ 65	$ 49
Debt, fair value (in dollars)	6,976	6,030
Other liabilities, fair value (in dollars)	529	193
Other assets of consolidated investment entities, fair value	$ 2,129	$ 1,936