CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 1,602.0	$ 1,999.9	$ 1,449.9
Other comprehensive income (loss):
Foreign currency translation adjustments	(26.1)	(49.8)	27.4
Pension liability adjustment	1.6	(8.6)	3.2
Net unrealized gains (losses) related to cash flow hedges:
Unrealized holding gains (losses)	410.5	568.1	(3.2)
Tax (expense) benefit	7.2	12.3	(2.6)
Unrealized holding gains (losses), net of tax	417.7	580.4	(5.8)
Reclassification adjustment for (gains) included in net income	(348.7)	(23.1)	(7.3)
Tax (benefit)	(2.2)	(1.7)	(6.9)
Reclassification adjustment for (gains) included in net income, net of tax	(350.9)	(24.8)	(14.2)
Net unrealized gains (losses) on marketable securities available for sale:
Unrealized holding gains (losses)	(314.4)	494.0	205.1
Tax (expense) benefit	109.8	(173.9)	(77.1)
Unrealized holding gains (losses), net of tax	(204.6)	320.1	128.0
Reclassification adjustment for losses included in net income	23.4	5.4	7.3
Tax (benefit)	(8.2)	(1.9)	(2.2)
Reclassification adjustment for losses included in net income, net of tax	15.2	3.5	5.1
Total other comprehensive income (loss)	(147.1)	820.8	143.7
Comprehensive income	$ 1,454.9	$ 2,820.7	$ 1,593.6