Unsecured short-term debt instrument issued by corporations which are 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. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash Equivalents

-URI http://asc.fasb.org/extlink&oid=6507016

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3052-108585

Financing Arrangements (Details) (USD $)	0 Months Ended	9 Months Ended		9 Months Ended
Financing Arrangements (Details) (USD $)	Dec. 31, 2013	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 Credit facility maturing September, 2019	Sep. 30, 2014 Credit facility maturing September, 2015	Sep. 30, 2014 Credit facility maturing June, 2016	Dec. 31, 2013 Credit facility maturing June, 2016	Sep. 30, 2014 Letter of credit subfacility	Aug. 15, 2014 Debt Matured August, 2014	May 01, 2014 Debt Matured May, 2014	Feb. 25, 2014 Debt Issued Due 2017	Feb. 25, 2014 Debt Issued Due 2019	Feb. 25, 2014 Debt Issued Due 2024
Debt Instrument [Line Items]
Debt Instrument, Face Amount									$ 100,000,000	$ 500,000,000	$ 250,000,000	$ 250,000,000	$ 300,000,000
Debt Instrument, Interest Rate, Stated Percentage									6.45%	8.60%	1.35%	2.40%	4.00%
Repurchase of Notes, Purchase Price Percentage of Principle Amount		101.00%
Line of Credit Facility, Initiation Date				Sep. 26, 2014	Sep. 26, 2014
Line of Credit Facility, Maximum Borrowing Capacity				2,000,000,000	1,000,000,000	1,725,000,000
Line of Credit Facility, Maximum Borrowing Capacity Through Accordion Feature				2,500,000,000
Line of Credit Facility, Expiration Date				Sep. 26, 2019	Sep. 25, 2015	Jun. 28, 2016
Line of Credit Facility, Current Borrowing Capacity								200,000,000
Debt Instrument, Basis Spread on Variable Rate				(1) the spread over LIBOR is 1.250%; (2) the spread over prime is 0.250%;	(1) the spread over LIBOR is 1.250%; (2) the spread over prime is 0.250%;
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage				0.15%	0.125%
Maximum rolling twelve month Leverage Ratio		3.25 to 1.0
Rolling twelve month Interest Coverage Ratio		3.0 to 1.0
Line of Credit Facility, Outstanding Amount				0	0		0
Line of Credit, up-front fee		2,700,000
Line of Credit Facility, Covenant Compliance	We were in compliance with financial covenant requirements	We were in compliance with financial covenant requirements
Commercial Paper		460,000,000	0
Short-term Bank Loans and Notes Payable		$ 26,000,000	$ 10,000,000