Accounting Changes and Recent Accounting Pronouncements (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Jan. 01, 2018	Dec. 31, 2017
Assets:
Trade receivables, net	$ 1,623.6		$ 1,537.2	$ 1,540.4
Other current assets	599.5		540.8	363.5
Investments and related note receivables	6,862.2		6,862.6	6,671.4
Deferred tax assets	3,266.0		3,141.2	3,157.2
Other assets, net	4,282.9		4,217.0	4,166.5
Liabilities:
Deferred revenue	1,230.0		1,080.4	1,048.1
Other accrued and current liabilities	2,211.4		1,922.0	1,920.8
Other long-term liabilities	3,926.3		3,152.5	3,110.7
Equity:
Accumulated deficit	(7,084.0)		(5,897.5)	(6,217.6)
Accumulated other comprehensive earnings, net of taxes	2,248.2			1,656.0
Noncontrolling interests	(397.9)		(407.6)	$ (412.0)
Reclassification to other income, net	$ 9.3	$ 16.0
Accounting Standards Update 2014-09 [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Assets:
Trade receivables, net			(3.2)
Other current assets			177.3
Investments and related note receivables			191.2
Deferred tax assets			(16.0)
Other assets, net			50.5
Liabilities:
Deferred revenue			32.3
Other accrued and current liabilities			1.2
Other long-term liabilities			41.8
Equity:
Accumulated deficit			320.1
Noncontrolling interests			$ 4.4
Accounting Standards Update 2017-07 [Member] | Selling, General and Administrative Expenses [Member]
Equity:
Reclassification to other income, net		3.2
Accounting Standards Update 2017-07 [Member] | Other Operating Expense [Member]
Equity:
Reclassification to other income, net		$ 0.9