Investments (allowance for credit losses rollforward) (Details) - Ameriprise Financial - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021		Jun. 30, 2020
Rollforward of available-for-Sale securities allowance for credit losses
Beginning Balance	$ 0	$ 13	$ 11	[1]	$ 0	[1]
Additions for which credit losses were not previously recorded					13
Additional increases (decreases) on securities that had an allowance recorded in a previous period		1			1
Charge-offs	0		(11)
Ending Balance	0	14	0		14
Corporate debt securities
Rollforward of available-for-Sale securities allowance for credit losses
Beginning Balance	0	13	10	[1]	0	[1]
Additions for which credit losses were not previously recorded					13
Additional increases (decreases) on securities that had an allowance recorded in a previous period		0
Charge-offs	0		(10)
Ending Balance	0	13	0		13
Asset backed securities
Rollforward of available-for-Sale securities allowance for credit losses
Beginning Balance	0	0	1	[1]	0	[1]
Additional increases (decreases) on securities that had an allowance recorded in a previous period		1			1
Charge-offs	0		(1)
Ending Balance	$ 0	$ 1	$ 0		$ 1

[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.