Investments (allowance for credit losses rollforward) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Ameriprise Financial [Member]
Rollforward of available-for-Sale securities allowance for credit losses
Beginning Balance	$ 11	$ 0	[1]
Debt Securities, Available-for-sale, Allowance for Credit Loss, Not Previously Recorded		(13)
Charge-offs	(11)
Ending Balance	0	13
Corporate debt securities [Member]
Rollforward of available-for-Sale securities allowance for credit losses
Beginning Balance	10
Corporate debt securities [Member] | Ameriprise Financial [Member]
Rollforward of available-for-Sale securities allowance for credit losses
Beginning Balance	10	0	[1]
Debt Securities, Available-for-sale, Allowance for Credit Loss, Not Previously Recorded		(13)
Charge-offs	(10)
Ending Balance	0	$ 13
Asset backed securities [Member]
Rollforward of available-for-Sale securities allowance for credit losses
Beginning Balance	1
Debt Securities, Available-for-sale, Allowance for Credit Loss, Not Previously Recorded	0
Additional increases (decreases) on securities that had an allowance recorded in a previous period	(1)
Asset backed securities [Member] | Ameriprise Financial [Member]
Rollforward of available-for-Sale securities allowance for credit losses
Beginning Balance	1
Charge-offs	(1)
Ending Balance	$ 0

[1] Prior to January 1, 2020, credit losses on Available-for-Sale securities were not recorded in an allowance but were recorded as a reduction of the book value of the security if the security was other-than-temporarily impaired.