Earnings per Share Attributable to Ameriprise Financial, Inc. Common Shareholders (Basic & Diluted) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Numerator:
Net income	$ 437	$ 2,036
Denominator:
Basic: Weighted-average common shares outstanding	119.8	126.4
Effect of potentially dilutive nonqualified stock options and other share-based awards (in shares)	2.4	1.8
Diluted: Weighted-average common shares outstanding	122.2	128.2
Basic:
Net income (in dollars per share)	$ 3.65	$ 16.11
Diluted:
Net income (in dollars per share)	$ 3.58	$ 15.88
Options excluded from earnings per share calculation due to their anti-dilutive effect (in shares)	0.3	4.5