Carrying value as of the balance sheet date of short-term borrowings using unsecured obligations issued by banks, corporations and other borrowers to investors. The maturities of these money market securities generally do not exceed 270 days.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Interest and debt related expenses associated with nonoperating financing activities of the entity.

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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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Debt and Lines of Credit - Additional Information (Details) - USD ($)	1 Months Ended	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2017	Mar. 31, 2016	Apr. 27, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Commercial paper	$ 0	$ 0
Retirement of long-term debt	250,000,000
Long-term debt, gross	3,375,000,000	3,375,000,000			$ 3,625,000,000
Interest and debt expense		18,000,000	$ 22,000,000
Subsequent Event
Debt Instrument [Line Items]
Long-term debt, gross				$ 600,000,000
Revolving credit facility
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity until March 2022	$ 2,000,000,000	$ 2,000,000,000