Common Stock Repurchase (Details) shares in Millions, $ in Millions	3 Months Ended
	Apr. 30, 2016 USD ($) shares
Common Stock Repurchase (Textual) [Abstract]
Amount authorized to repurchase company's common stock	$ 6,200.0
Number of company's common stock repurchased | shares	146.6
Amount paid for repurchase of company's common stock	$ 5,400.0
Remaining amount to repurchase company common stock under authorized program	$ 814.8