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		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Numerator:
Net income	$ 503	$ 507	$ 1,559	$ 1,303
Denominator:
Basic: Weighted-average common shares outstanding	144.4	153.0	147.0	155.2
Effect of potentially dilutive nonqualified stock options and other share-based awards (in shares)	2.1	2.4	2.2	2.4
Diluted: Weighted-average common shares outstanding	146.5	155.4	149.2	157.6
Basic:
Net income (in dollars per share)	$ 3.48	$ 3.31	$ 10.61	$ 8.40
Diluted:
Net income (in dollars per share)	$ 3.43	$ 3.26	$ 10.45	$ 8.27
Effect of potentially dilutive nonqualified stock options and other share-based awards (in shares)			1.0	0.0