Shareholders' Equity (Narrative) (Details) - USD ($)					1 Months Ended	3 Months Ended		32 Months Ended
	Oct. 08, 2018	Aug. 02, 2018	Oct. 30, 2017	Jul. 29, 2016	Feb. 28, 2019	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Jul. 31, 2018
Equity Class Of Treasury Stock [Line Items]
Shares repurchase program, repurchased cost						$ 20,000,000	$ 70,000,000
Quarterly dividends declared					$ 0.175
Dividends declared						$ 0.175
Dividends payable, date to be paid, year and month						2019-03		2019-03
Accelerated Share Repurchase [Member] | Deutsche Bank AG [Member]
Equity Class Of Treasury Stock [Line Items]
Shares repurchase program, expiration date						Oct. 08, 2018
Pre payment of repurchase program		$ 150,000,000
Repurchase program, Shares		1,766,004
Accelerated share repurchase remaining shares returned	389,825
Common Stock
Equity Class Of Treasury Stock [Line Items]
Shares repurchase program, expiration date				Jul. 31, 2018
Stock repurchase program, additional authorized amount			$ 250,000,000						$ 300,000,000
Shares repurchase program, extended expiration date			Oct. 31, 2020
Shares repurchase program, shares repurchased						331,686	1,165,247
Common Stock | Share Repurchase Program Excluding ASR [Member]
Equity Class Of Treasury Stock [Line Items]
Shares repurchase program, shares repurchased						300,000		8,000,000
Shares repurchase program, repurchased cost						$ 20,000,000		$ 450,600,000
Shares repurchase program, average price per share						$ 60.30		$ 56.19
Common Stock | Maximum [Member]
Equity Class Of Treasury Stock [Line Items]
Shares repurchase program, authorized amount				$ 150,000,000					$ 700,000,000