Investments (Number of Securities Included in Loss Position of Current and Noncurrent Investments) (Details)	Sep. 30, 2015 Securities
Current [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months	646
12 Months or More	70
Total, number of securities	716
Current [Member] | Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months	153
12 Months or More	29
Total, number of securities	182
Current [Member] | U.S. Government and Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months	1
12 Months or More	0
Total, number of securities	1
Current [Member] | Obligations of States and Other Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months	149
12 Months or More	11
Total, number of securities	160
Current [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months	343
12 Months or More	30
Total, number of securities	373
Noncurrent [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months	13
12 Months or More	13
Total, number of securities	26
Noncurrent [Member] | Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months	0
12 Months or More	1
Total, number of securities	1
Noncurrent [Member] | Obligations of States and Other Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months	0
12 Months or More	1
Total, number of securities	1
Noncurrent [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months	13
12 Months or More	11
Total, number of securities	24