Debt instrument redemption amount.

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- Definition

Number Of Cash Tender Offers

+ References

No definition available.

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- Definition

This item represents the gain (loss) realized during the period from the sale of investments accounted for under the cost method of accounting and any losses recognized thereon for impairments of other than a temporary nature.

+ References

No definition available.

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- Definition

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

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- Definition

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

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- Definition

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.

+ References

No definition available.

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- Definition

Fair value amount of debt instrument that was repurchased.

+ References

No definition available.

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- Definition

Amount of the cost of borrowed funds accounted for as interest expense.

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- Definition

Amount of the cost of borrowed funds accounted for as interest expense for debt.

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- Definition

Amount of cash paid for interest, including, but not limited to, capitalized interest and payment to settle zero-coupon bond attributable to accreted interest of debt discount and debt instrument with insignificant coupon interest rate in relation to effective interest rate of borrowing attributable to accreted interest of debt discount; classified as operating and investing activities.

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- Definition

The amount of expense provided in the period for legal costs incurred on or before the balance sheet date pertaining to resolved, pending or threatened litigation, including arbitration and mediation proceedings.

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- Definition

Interest received on loans and other debt instruments during the current period.

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- Definition

The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

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- Definition

The number of shares issued or sold by the subsidiary or equity method investee per stock transaction.

+ References

No definition available.

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Per share amount received by subsidiary or equity investee for each share of common stock issued or sold in the stock transaction.

+ References

No definition available.

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Debt - Public Debt (Details)		1 Months Ended	2 Months Ended	3 Months Ended	12 Months Ended
Debt - Public Debt (Details)	Oct. 02, 2017 shares	Sep. 30, 2014 shares	May 31, 2017 USD ($) $ / shares	Jun. 30, 2017 USD ($) cash_tender_offer $ / shares shares	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Oct. 15, 2019 USD ($)	Mar. 31, 2018 USD ($)
Debt Instrument [Line Items]
Interest charge related to early redemption of notes				$ 58,000,000		$ 19,000,000
Cash paid to holders of debt instrument, net				$ 409,000,000
Common stock sold (in shares) \| shares	24,022	25,000,000		12,958,767
Common stock sold per share (usd per share) \| $ / shares				$ 35.91
Debt instrument, repurchase amount				$ 874,000,000
Interest paid				27,000,000
Legal fees				2,000,000
Pre-tax gain on sale of common stock				167,000,000			$ 167,000,000
Interest expense				24,000,000	$ 338,000,000	$ 378,000,000	$ 496,000,000
Interest Rate Swap
Debt Instrument [Line Items]
Proceeds from interest received				8,000,000
Investment Banks
Debt Instrument [Line Items]
Debt instrument, face amount				$ 805,000,000
Number of cash tender offers \| cash_tender_offer				3
Common stock sold per share (usd per share) \| $ / shares			$ 35.91
Pre-tax gain on sale of common stock			$ 167,000,000
Investment Banks \| Maximum
Debt Instrument [Line Items]
Debt instrument, face amount				$ 1,000,000,000
1.63% Convertible Notes, due 2019
Debt Instrument [Line Items]
Convertible notes, interest rate percentage					1.63%			1.63%
Debt instrument, repurchase amount								$ 403,000,000
6.150% Notes, due 2020
Debt Instrument [Line Items]
Convertible notes, interest rate percentage					6.15%
5.40% Notes, due 2021
Debt Instrument [Line Items]
Convertible notes, interest rate percentage					5.40%
5.87% Notes, due 2022
Debt Instrument [Line Items]
Convertible notes, interest rate percentage					5.87%
5.125% Notes, due 2024
Debt Instrument [Line Items]
Convertible notes, interest rate percentage					5.125%
5.90% Notes, due 2027
Debt Instrument [Line Items]
Convertible notes, interest rate percentage					5.90%
6.75% Bonds, due 2028
Debt Instrument [Line Items]
Convertible notes, interest rate percentage					6.75%
5.95% Notes due 2037
Debt Instrument [Line Items]
Convertible notes, interest rate percentage					5.95%
Iowa Finance Authority Loan, due 2042 (4.75%)
Debt Instrument [Line Items]
Convertible notes, interest rate percentage					4.75%
5.72% Notes due 2019
Debt Instrument [Line Items]
Convertible notes, interest rate percentage					5.72%	5.72%	5.72%		5.72%
Debt instrument, face amount									$ 500,000,000
Debt instrument redemption amount									$ 518,000,000
5.72% Notes due 2019 \| Investment Banks
Debt Instrument [Line Items]
Debt instrument, face amount				$ 250,000,000
6.5% Bonds due 2018
Debt Instrument [Line Items]
Convertible notes, interest rate percentage				6.50%		6.50%
Debt instrument, face amount				$ 100,000,000
6.5% Bonds due 2018 \| Investment Banks
Debt Instrument [Line Items]
Debt instrument, face amount				$ 150,000,000
6.75% Notes due 2018
Debt Instrument [Line Items]
Convertible notes, interest rate percentage				6.75%		6.75%	6.75%
Debt instrument, face amount				$ 345,000,000
Debt instrument redemption amount				479,000,000
6.75% Notes due 2018 \| Investment Banks
Debt Instrument [Line Items]
Debt instrument, face amount				$ 405,000,000