Consolidated Balance Sheet (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Fixed maturities, available for sale at amortized cost	$ 41,837	$ 37,038
Common Stock, par value (USD per share)	$ 0	$ 0
Common Stock, shares authorized	200,000,000	200,000,000
Common Stock, shares outstanding	89,291,724	88,275,460