Segment Information - Reportable Segments and Total Assets (Details) $ in Millions	9 Months Ended
	Sep. 30, 2021 USD ($) segement	Dec. 31, 2020 USD ($)
Segment Reporting [Abstract]
Number of reportable segments | segement	4
Summary of assets by segment
Total assets	$ 170,726	$ 165,883
Reportable segments | Advice and Wealth Management Segment
Summary of assets by segment
Total assets	22,849	21,266
Reportable segments | Asset Management Segment
Summary of assets by segment
Total assets	9,213	8,406
Reportable segments | Retirement and Protection Solutions Segment
Summary of assets by segment
Total assets	116,986	114,850
Reportable segments | Nonsegment
Summary of assets by segment
Total assets	$ 21,678	$ 21,361