Equity (Details Textual) - USD ($) shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Sep. 30, 2016	Jun. 30, 2015	Mar. 31, 2011
Class of Stock [Line Items]
Preferred stock, shares authorized	8,000
Equity (Textual)
Authorized amount of share repurchases under the 2015 Share Repurchase Program				$ 5,000.0	$ 5,000.0
Repurchase of common stock, shares	3,300	16,800	2,900
Repurchase of common stock, value	$ 1,000.0	$ 5,000.0	$ 886.8
Common stock shares authorized for repurchase	1,300					20,000
Series A
Class of Stock [Line Items]
Preferred stock, shares authorized	1,750
Series X junior participating
Class of Stock [Line Items]
Preferred stock, shares authorized	1,000
Undesignated
Class of Stock [Line Items]
Preferred stock, shares authorized	5,250