Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Fair value amount of debt instrument that was repurchased.

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Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average interest rate of debt outstanding.

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Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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The effective interest rate at the end of the reporting period.

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

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Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

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Debt (Narrative) (Details) - USD ($)		1 Months Ended					3 Months Ended	6 Months Ended
Debt (Narrative) (Details) - USD ($)	Jun. 30, 2015	Mar. 31, 2015	Oct. 31, 2014	Sep. 30, 2014	May. 31, 2014	Dec. 31, 2012	Dec. 31, 2014	Jun. 30, 2015	Jun. 30, 2014
Debt Instrument [Line Items]
Cash outflow on redemption of debt								$ 5,000,000	$ 5,000,000
Senior Debt Obligations Due 2020 [Member]
Debt Instrument [Line Items]
Proceeds from issuance of debt		$ 500,000,000
Interest rate	2.35%	2.35%						2.35%
Term of debt		5 years
2.35% Senior Debt Obligations Due 2019 [Member]
Debt Instrument [Line Items]
Proceeds from issuance of debt				$ 300,000,000
Interest rate	2.35%			2.35%				2.35%
Term of debt				5 years
3.50% Senior Debt Obligations Due 2025 [Member]
Debt Instrument [Line Items]
Proceeds from issuance of debt				$ 500,000,000
Interest rate	3.50%			3.50%				3.50%
Term of debt				10 years 6 months
Senior Debt Obligations Due 2019 [Member]
Debt Instrument [Line Items]
Interest rate	9.25%							9.25%
Senior Debt Obligations Due 2024 [Member]
Debt Instrument [Line Items]
Proceeds from issuance of debt					$ 600,000,000
Interest rate	3.50%				3.50%			3.50%
Term of debt					10 years
Senior Debt Obligations Due 2014 [Member]
Debt Instrument [Line Items]
Interest rate					5.375%
Senior Debt Obligations Due 2023 [Member]
Debt Instrument [Line Items]
Interest rate	4.05%							4.05%
Amended Revolving Credit Facility March 27, 2014 [Member]
Debt Instrument [Line Items]
Term of debt	5 years
Debt facilities, maximum borrowing capacity	$ 1,200,000,000							$ 1,200,000,000
Revolving credit facility, amount outstanding	0							0
Term Loan Facility - due 2016
Debt Instrument [Line Items]
Term of debt						3 years
Debt facilities, maximum borrowing capacity						$ 50,000,000
Revolving credit facility, amount outstanding	$ 50,000,000							$ 50,000,000
Interest rate on three-year draw term loan facility	1.19%							1.19%
Senior Debt Obligations Due 2015 and Senior Debt Obligations Due 2019 [Member]
Debt Instrument [Line Items]
Debt partial redemption amount			$ 630,000,000
Cash outflow on redemption of debt			$ 765,000,000
Cost for early redemption							$ 137,000,000
Senior Debt Obligations Due 2019 [Member]
Debt Instrument [Line Items]
Interest rate			9.25%
Debt partial redemption amount			$ 400,000,000
Senior Debt Obligations Due 2014 [Member]
Debt Instrument [Line Items]
Cash outflow on redemption of debt					$ 320,000,000
Senior Debt Obligations Due 2015 [Member]
Debt Instrument [Line Items]
Interest rate			5.75%
Debt partial redemption amount			$ 230,000,000
Commercial Paper [Member]
Debt Instrument [Line Items]
Commercial paper	$ 50,000,000						$ 0	$ 50,000,000
Weighted average interest rate	0.54%							0.54%