Goodwill And Other Intangible Assets (Summary Of The Change In The Carrying Amount Of Goodwill By Reportable Segment) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Change in the carrying amount of goodwill by reportable segment
Goodwill, Beginning Balance	$ 16,917.2us-gaap_Goodwill	$ 16,889.8us-gaap_Goodwill
Measurement period adjustments	(1.8)	27.4
Other adjustments	166.6us-gaap_GoodwillPeriodIncreaseDecrease
Goodwill, Ending Balance	17,082.0us-gaap_Goodwill	16,917.2us-gaap_Goodwill
Accumulated impairment as of December 31, 2014	(41.0)
Commercial and Specialty Business [Member]
Change in the carrying amount of goodwill by reportable segment
Goodwill, Beginning Balance	11,554.0	11,555.3
Measurement period adjustments	(1.6)	(1.3)
Other adjustments	266.5
Goodwill, Ending Balance	11,818.9	11,554.0
Accumulated impairment as of December 31, 2014	(41.0)
Government Business [Member]
Change in the carrying amount of goodwill by reportable segment
Goodwill, Beginning Balance	5,363.2	5,334.5
Measurement period adjustments	(0.2)	28.7
Other adjustments	(99.9)
Goodwill, Ending Balance	5,263.1	5,363.2
Accumulated impairment as of December 31, 2014	$ 0

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=14024403&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

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Amount of accumulated impairment loss for an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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Amount of increase (decrease) of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of increase (decrease) from adjustments after acquisition date under purchase accounting of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (g)

-URI http://asc.fasb.org/extlink&oid=14024403&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 25

-Paragraph 16

-URI http://asc.fasb.org/extlink&oid=21917927&loc=d3e961-128460

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