CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions		Dec. 31, 2018	Dec. 31, 2017
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		328,537,214	327,506,935
Treasury shares		192,206,467	180,872,271
Consolidated investment entities [Member]
Receivables, fair value (in dollars)		$ 12	$ 25
Other assets, fair value (in dollars)		0	0
Debt, fair value (in dollars)	[1]	1,743	2,206
Other liabilities, fair value (in dollars)		$ 122	$ 63

[1] The carrying value of the CLOs’ debt is set equal to the fair value of the CLOs’ assets. The estimated fair value of the CLOs’ debt was $1.7 billion and $2.2 billion as of December 31, 2018 and 2017, respectively.