Shareholders' Equity (Narrative) (Details)		1 Months Ended	3 Months Ended		9 Months Ended	12 Months Ended
	Apr. 24, 2014 shares	Jan. 31, 2015 shares	Dec. 31, 2015 USD ($) shares	Sep. 30, 2015 USD ($)	Sep. 30, 2015 USD ($) shares	Dec. 31, 2015 USD ($) shares	Sep. 30, 2015 USD ($) shares	Dec. 31, 2014 shares	Oct. 31, 2014 USD ($)	Apr. 23, 2014 shares
Class of Stock [Line Items]
Stock split, conversion ratio	0.1429
Common stock, shares authorized | shares	2,400,000,000		342,857,143			342,857,143		342,857,143		1,200,000,000
Common Stock [Member]
Class of Stock [Line Items]
Stock repurchase program, repurchased amount					$ 161,900,000		$ 175,000,000
Stock repurchase program, shares repurchased | shares					5,673,686
Stock repurchase program, additional shares repurchased | shares							6,177,455
Repurchase of Common Stock 250 Million [Member] | Common Stock [Member]
Class of Stock [Line Items]
Stock repurchase program, authorized amount									$ 75,000,000.0
Stock repurchase program, repurchased amount				$ 250,000,000
Stock repurchase program, shares repurchased | shares		392,000				9,100,000.0		2,500,000.0
Repurchase of Common Stock 300 Million [Member] | Common Stock [Member]
Class of Stock [Line Items]
Stock repurchase program, authorized amount				$ 300,000,000	$ 300,000,000		$ 300,000,000
Stock repurchase program, repurchased amount			$ 37,100,000
Stock repurchase program, period in force				15 months
Stock repurchase program, shares repurchased | shares			1,200,000
Remaining authorized repurchase amount			$ 262,900,000			$ 262,900,000