3. Available-for-Sale Investments (Details) (Fair Value, Measurements, Recurring [Member], USD $) In Millions, unless otherwise specified	6 Months Ended		12 Months Ended
	Jun. 30, 2014		Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 310.7		$ 327.2
Unrealized Gains	248.4		244.6
Unrealized Losses	(0.3)		(0.9)
Estimated Fair Value	558.8		570.9
Other Long-term Investments [Member] | Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	0.3		0.4
Unrealized Gains	0		0
Unrealized Losses	0		(0.1)
Estimated Fair Value	0.3		0.3
Other Long-term Investments [Member] | Marketable Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	54.5		54.5
Unrealized Gains	241.1		238.7
Unrealized Losses	0		0
Estimated Fair Value	295.6		293.2
Other Long-term Investments [Member] | Available-for-sale Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	54.8		54.9
Unrealized Gains	241.1		238.7
Unrealized Losses	0		(0.1)
Estimated Fair Value	295.9		293.5
Short-term Investments [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	120.0		132.6
Unrealized Gains	0.5		0.3
Unrealized Losses	(0.1)		(0.4)
Estimated Fair Value	120.4		132.5
Short-term Investments [Member] | Foreign Brokered Certificates of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	5.1		8.9
Unrealized Gains	0		0
Unrealized Losses	0		0
Estimated Fair Value	5.1		8.9
Short-term Investments [Member] | Municipal obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	8.1		11.1
Unrealized Gains	0		0
Unrealized Losses	(0.1)		(0.1)
Estimated Fair Value	8.0		11.0
Short-term Investments [Member] | Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	50.4		48.4
Unrealized Gains	0.1		0.1
Unrealized Losses	(0.1)		(0.2)
Estimated Fair Value	50.4		48.3
Short-term Investments [Member] | Marketable Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	26.6		26.6
Unrealized Gains	6.6		5.4
Unrealized Losses	0		0
Estimated Fair Value	33.2		32.0
Short-term Investments [Member] | Available-for-sale Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	255.9		272.3
Unrealized Gains	7.3		5.9
Unrealized Losses	(0.3)		(0.8)
Estimated Fair Value	262.9		277.4
Short-term Investments [Member] | US Government Sponsored Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	41.9		39.1
Unrealized Gains	0.1		0.1
Unrealized Losses	0		(0.1)
Estimated Fair Value	42.0		39.1
Short-term Investments [Member] | Foreign Government Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3.8		5.6
Unrealized Gains	0		0
Unrealized Losses	0		0
Estimated Fair Value	3.8		5.6
Estimate of Fair Value, Fair Value Disclosure [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	558.8	[1]	570.9	[1]
Estimate of Fair Value, Fair Value Disclosure [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	120.4	[1]	132.5	[1]
Estimate of Fair Value, Fair Value Disclosure [Member] | Foreign Brokered Certificates of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	5.1	[1]	8.9	[1]
Estimate of Fair Value, Fair Value Disclosure [Member] | Municipal obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	8.0	[1]	11.0	[1]
Estimate of Fair Value, Fair Value Disclosure [Member] | Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	50.7	[1]	48.6	[1]
Estimate of Fair Value, Fair Value Disclosure [Member] | Marketable Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	328.8	[1]	325.2	[1]
Estimate of Fair Value, Fair Value Disclosure [Member] | US Government Sponsored Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	42.0	[1]	39.1	[1]
Estimate of Fair Value, Fair Value Disclosure [Member] | Foreign Government Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	3.8	[1]	5.6	[1]
Estimate of Fair Value, Fair Value Disclosure [Member] | Short-term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	$ 262.9		$ 277.4

[1] Available-for-sale investments are included in the following accounts in the Condensed Consolidated Balance Sheets (in millions): June 30, 2014 December 31, 2013Short-term investments$262.9 $277.4Other investments295.9 293.5Total$558.8 $570.9