CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
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	316,115,977	309,399,529
Treasury shares	120,876,387	105,456,535
Consolidated Investment Entities
Receivables, fair value (in dollars)	$ 26	$ 77
Debt, fair value (in dollars)	4,459	4,450
Other liabilities, fair value (in dollars)	$ 94	$ 166