CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Jun. 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	322,563,052	320,990,255
Treasury shares	143,813,440	137,880,746
Consolidated investment entities [Member]
Receivables, fair value (in dollars)	$ 39	$ 49
Debt, fair value (in dollars)	6,487	6,030
Other liabilities, fair value (in dollars)	$ 238	$ 193