Consolidated Balance Sheets (Parenthetical) $ in Millions	Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 USD ($) shares
Statement of Financial Position [Abstract]
Fixed maturities available for sale, at amortized cost	$ 79,536	$ 43,149
Fixed maturities available for sale, hybrid financial instruments	2	31
Held-to-maturity Securities, Fair Value	10,670	8,552
Equity securities, at cost	706	441
Other investments, cost	$ 4,270	$ 2,993
Common Shares, shares issued | shares	479,783,864	342,832,412
Common Shares, shares outstanding | shares	465,968,716	324,563,441
Common Shares in treasury, shares | shares	13,815,148	18,268,971