Investments Narrative (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Corporate securities [Member]
Short Term Investments And Cash Equivalents	$ 1,800	$ 1,100
Federal government securities [Member]
Short Term Investments And Cash Equivalents	544	167
Money Market Funds [Member]
Short Term Investments And Cash Equivalents	$ 142	$ 217

Cash equivalents represent the amount of short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation. Short-term investments are intended to be sold in the short term (usually less than one year or the normal operating cycle, whichever is longer) including trading securities, available-for-sale securities, held-to-maturity securities, and other short-term investments not otherwise listed in the existing taxonomy.

No definition available.

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Namespace Prefix:	ci_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant