Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial assets (liabilities)
Cash and equivalents	$ 11	$ 23
Available-for-sale debt securities	0
Available-for-sale debt securities		0
Equity securities	54	52
Other investments	0
Other investments		0
Cash flow hedges	0	0
Short- and long-term debt principal	0	0
Significant Other Observable Inputs (Level 2)
Financial assets (liabilities)
Cash and equivalents	13	6
Available-for-sale debt securities	129
Available-for-sale debt securities		121
Equity securities	0	0
Other investments	0
Other investments		0
Cash flow hedges	26	(69)
Short- and long-term debt principal	(12,339)	(12,346)
Significant Unobservable Inputs (Level 3)
Financial assets (liabilities)
Cash and equivalents	0	0
Available-for-sale debt securities	0
Available-for-sale debt securities		0
Equity securities	0	0
Other investments	4
Other investments		4
Cash flow hedges	0	0
Short- and long-term debt principal	0	0
Carrying Value
Financial assets (liabilities)
Cash and equivalents	24	29
Available-for-sale debt securities	129
Available-for-sale debt securities		121
Equity securities	54	52
Other investments	4
Other investments		4
Cash flow hedges	26	(69)
Short- and long-term debt principal	(12,005)	(12,518)
Fair Value
Financial assets (liabilities)
Cash and equivalents	24	29
Available-for-sale debt securities	129
Available-for-sale debt securities		121
Equity securities	54	52
Other investments	4
Other investments		4
Cash flow hedges	26	(69)
Short- and long-term debt principal	$ (12,339)	$ (12,346)

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, 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.

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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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Amount of investments classified as other.

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