Supplemental Cash Flow Information - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Abstract]
Transfer from Investments	$ 21	$ 128
Non-cash financing activities related to the issuance of shares for vested restricted stock units	51	$ 46
Operating lease, payments	39
ROU asset obtained in exchange for operating lease liability	$ 31