Investments - Summary (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019	[1]
Summary of investments
Allowance for credit losses	$ 51	$ 68	$ 71	$ 51
Ameriprise Financial
Summary of investments
Available-for-Sale: Fixed maturities, at fair value	30,114	36,283
Mortgage loans, net	1,911	2,718
Policy loans	836	846
Other investments	657	1,184
Investments	33,518	41,031
Ameriprise Financial | Mortgage loans
Summary of investments
Allowance for credit losses	14	29
Ameriprise Financial | Other investments
Summary of investments
Allowance for credit losses	$ 4	$ 12

[1] Prior to January 1, 2020, the allowance for credit losses was based on an incurred loss model that did not require estimating expected credit losses over the expected life of the asset.