Shareholders' Equity Changes in Stockholders' Equity (Details) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Mar. 31, 2019	Jun. 30, 2017
Stock repurchase program, authorized amount				$ 2,500	$ 2,500
Remaining balance under stock repurchase program	$ 509
Number of shares reacquired through surrender of restricted shares	0.3	0.3	0.3
Value of shares reacquired through surrender of restricted shares	$ 44	$ 33	$ 29
Number of shares reacquired through net settlement of options	0.5	2.2	0.5
Aggregate value of shares reacquired through net settlement of options	$ 85	$ 298	$ 48
Treasury shares reissued for restricted stock award grants and Ameriprise Financial Franchise Advisor Deferred Compensation Plan	0.8	0.8	0.9
Open Market Share Repurchases [Member]
Repurchase of common shares (in shares)	11.3	9.9	17.6
Repurchase of common shares	$ 1,600	$ 1,300	$ 1,700