Equity (Details) - USD ($) $ / shares in Units, shares in Millions		3 Months Ended				6 Months Ended
		Dec. 31, 2015	Jun. 30, 2015		Mar. 31, 2015	Jun. 30, 2016	Jun. 30, 2015
Dividends Payable [Line Items]
Common Stock, Dividends, Per Share, Cash Paid	[1]		$ 0.885		$ 0.885
Dividends, Common Stock, Cash	[1]		$ 300,800,000		$ 300,000,000
Common stock repurchased during period, shares						0.3
Purchases of capital stock						$ 24,460,000	$ 29,490,000
Common Stock [Member]
Dividends Payable [Line Items]
Dividends Payable, Date Declared	[1]		May 20, 2016		Feb. 18, 2016
Dividends Payable, Date to be Paid	[1]		Jun. 30, 2016		Mar. 31, 2016
Dividends Payable, Date of Record	[1]		Jun. 17, 2016		Mar. 18, 2016
Mandatory Convertible Preferred stock [Member]
Dividends Payable [Line Items]
Dividends Payable, Date Declared		Dec. 16, 2015			Mar. 22, 2016
Dividends Payable, Date to be Paid		Feb. 01, 2016			May 02, 2016
Dividends Payable, Date of Record		Jan. 16, 2016			Apr. 15, 2016
Preferred Stock, Dividends, Per Share, Cash Paid		$ 1.1250	$ 1.1250	[2]	$ 1.1250
Dividends, Preferred Stock, Cash		$ 11,000,000	$ 11,000,000	[2]	$ 11,000,000
Mandatory Convertible Preferred stock [Member] | Paid subsequent to quarter end [Member]
Dividends Payable [Line Items]
Dividends Payable, Date Declared	[2]		Jun. 28, 2016
Dividends Payable, Date to be Paid	[2]		Aug. 01, 2016
Dividends Payable, Date of Record	[2]		Jul. 15, 2016

[1] Inclusive of dividends accrued for holders of unvested restricted stock units and payments of previously accrued dividends for holders of restricted stock units that have vested during the six months ended June 30, 2016.

[2] Represents amount paid on August 1, 2016 based on holders of record on July 15, 2016.