Stock Repurchase Programs (Details) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	1 Months Ended	3 Months Ended	6 Months Ended	1 Months Ended	3 Months Ended	6 Months Ended	1 Months Ended	6 Months Ended
Mar. 31, 2013 2013 Stock Plan	Aug. 03, 2013 2013 Stock Plan	Aug. 03, 2013 2013 Stock Plan	Feb. 29, 2012 2012 Stock Plan	Jul. 28, 2012 2012 Stock Plan	Aug. 03, 2013 2012 Stock Plan	May 31, 2011 May 2011 Stock Plan	Jul. 28, 2012 May 2011 Stock Plan
Stock Repurchase Programs
Stock repurchase authorization	$ 250			$ 250			$ 250
Number of shares repurchased		0	300		2,100	1,200		439
Amount of shares repurchased			22.7		134.6	92.0		27.5
Average price of shares repurchased (in dollars per share)			$ 79.04		$ 64.52	$ 79.14		$ 62.71
Repurchase of common stock remaining authorization			$ 227.3

Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method.

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

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 12

-Paragraph 10

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187085-122770

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 30

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6405813&loc=d3e23239-112655

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

-Number 43

-Section B

-Paragraph 7

-Subparagraph b

-Chapter 1

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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