Segment Information (Premium Revenue By Line Of Business) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting Information [Line Items]
Health plans services premiums	$ 2,881,345	$ 2,632,069
Commercial Premium Revenue [Member]
Segment Reporting Information [Line Items]
Health plans services premiums	1,264,200	1,325,400
Medicare Premium Revenue [Member]
Segment Reporting Information [Line Items]
Health plans services premiums	755,200	706,400
Medicaid Premium Revenue [Member]
Segment Reporting Information [Line Items]
Health plans services premiums	$ 862,000	$ 600,300