Consolidated Balance Sheets (Parenthetical) $ in Millions	Jun. 30, 2015 USD ($) shares	Dec. 31, 2014 USD ($) shares
Statement of Financial Position [Abstract]
Fixed maturities available for sale, at amortized cost	$ 47,599	$ 47,826
Fixed maturities available for sale, hybrid financial instruments	282	274
Fixed maturities held to maturity, at amortized cost	8,805	7,589
Equity securities, at cost	433	440
Other investments, cost	$ 2,989	$ 2,999
Common Shares, shares issued | shares	342,832,412	342,832,412
Common Shares, shares outstanding | shares	323,814,281	328,659,686
Common Shares in treasury, shares | shares	19,018,131	14,172,726