Consolidated Balance Sheets (Parenthetical) $ in Millions	Dec. 31, 2015 USD ($) shares	Dec. 31, 2014 USD ($) shares
Statement of Financial Position [Abstract]
Fixed maturities available for sale, at amortized cost	$ 43,149	$ 47,826
Fixed maturities available for sale, hybrid financial instruments	31	274
Held-to-maturity Securities, Fair Value	8,552	7,589
Equity securities, at cost	441	440
Other investments, cost	$ 2,993	$ 2,999
Common Shares, shares issued | shares	342,832,412	342,832,412
Common Shares, shares outstanding | shares	324,563,441	328,659,686
Common Shares in treasury, shares | shares	18,268,971	14,172,726