Equity (Share Activity) (Narrative) (Details) - USD ($) shares in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 21, 2018	Sep. 11, 2018	Mar. 31, 2018	Dec. 31, 2016
Equity, Treasury Stock [Line Items]
Treasury stock acquired, value	$ 602,000	$ 319,001,000	$ 1,551,000
Treasury stock acquired (in shares)		7.2
Stock Repurchase Program, Remaining Authorized Repurchase Amount	128,800,000
September 2018 Share Repurchase Program [Member]
Equity, Treasury Stock [Line Items]
Treasury stock acquired, value		$ 120,600,000
Treasury stock acquired (in shares)		2.9
Share repurchase program, authorized amount, value					$ 150,000,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount	28,800,000
2016 Share Repurchase Program [Member]
Equity, Treasury Stock [Line Items]
Treasury stock acquired, value		$ 98,400,000
Treasury stock acquired (in shares)		2.0
Share repurchase program, authorized amount, value							$ 100,000,000
March 2018 Share Repurchase Program [Member]
Equity, Treasury Stock [Line Items]
Treasury stock acquired (in shares)		2.3
Share repurchase program, authorized amount, value						$ 100,000,000
December 2018 Share Repurchase Program [Member]
Equity, Treasury Stock [Line Items]
Share repurchase program, authorized amount, value				$ 100,000,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 100,000,000