Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Available-for-sale securities, at fair value:
Fixed maturity securities (amortized cost)	$ 94,295	$ 92,429
Stockholders' Equity
Preferred stock - shares authorized (in shares)	10,000,000	10,000,000
Common stock - shares authorized (in shares)	800,000,000	800,000,000
Common stock - shares issued (in shares)	196,668,532	205,862,760
Common stock - shares outstanding (in shares)	196,668,532	205,862,760