Discount in percentage terms at which long term debt was issued.

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- Definition

Long-Term Debt Qualifying as Risk Based Capital

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Outstanding Bank Notes Offering Capacity

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Amount equal to the present value (the principal) at the beginning of the lease term of minimum lease payments during the lease term (excluding that portion of the payments representing executory costs such as insurance, maintenance, and taxes to be paid by the lessor, together with any profit thereon) net of payments or other amounts applied to the principal through the balance sheet date.

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Amount of the increase (decrease) in fair value of the hedged item in a fair value hedge recognized in the income statement.

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- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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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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- Definition

Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

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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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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Amount of long-term debt classified as other.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of subordinated debt (with initial maturities beyond one year or beyond the operating cycle if longer). Subordinated debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets.

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Senior Notes and Long-Term Debt - Long-Term Debt (Detail) - USD ($)		12 Months Ended
	Nov. 06, 2013	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Capital Lease Obligations		$ 0	$ 14,400,000
Total Long-Term Debt		1,112,400,000	1,449,500,000
Long-Term Debt Qualifying as Risk-Based Capital		$ 1,099,500,000	1,099,400,000
Redemption price, percentage		100.00%
Fixed Rate Due Aug. 2022
Debt Instrument [Line Items]
Interest Rate		2.38%
Notes issued at a discount		0.283%
Fixed Rate Due Aug. 2028
Debt Instrument [Line Items]
Interest Rate		3.65%
Notes issued at a discount		0.125%
6.50% Notes due Aug. 2018
Debt Instrument [Line Items]
Long term debt		$ 0	305,500,000
Interest Rate		6.50%
Notes issued at a discount		0.02%
6.50% Notes due Aug. 2018 \| Lower Limit
Debt Instrument [Line Items]
Debt maturity	5 years
6.50% Notes due Aug. 2018 \| Upper Limit
Debt Instrument [Line Items]
Debt maturity	15 years
Corporation Subordinated Notes
Debt Instrument [Line Items]
Long term debt		$ 1,112,400,000	1,129,600,000
Corporation-Subordinated 3.95% Notes due Oct. 2025
Debt Instrument [Line Items]
Long term debt		$ 763,100,000	780,400,000
Interest Rate		3.95%
Notes issued at a discount		0.114%
Corporation Subordinated 3.375% Notes due May 2032
Debt Instrument [Line Items]
Long term debt		$ 349,300,000	349,200,000
Interest Rate		3.375%
Debt instrument, basis spread on variable rate		1.131%
Senior Notes
Debt Instrument [Line Items]
Offering Circular, ability to offer notes in aggregate principal amount	$ 4,500,000,000.0
Debt issue costs		$ 1,600,000
Senior Notes \| Lower Limit
Debt Instrument [Line Items]
Debt maturity	30 days
Senior Notes \| Upper Limit
Debt Instrument [Line Items]
Debt maturity	15 years
Subordinated Debt
Debt Instrument [Line Items]
Offering Circular, ability to offer notes in aggregate principal amount	$ 1,000,000,000
Subordinated Debt \| Interest Rate Swaps
Debt Instrument [Line Items]
Increases in the carrying values of notes outstanding covered by interest-rate swap contracts		29,300,000	$ 37,400,000
Long Term Debt
Debt Instrument [Line Items]
Debt issue costs		$ 1,400,000
Fixed Rate Due Nov. 2020
Debt Instrument [Line Items]
Interest Rate		3.45%
Notes issued at a discount		0.117%
Fixed Rate Due Aug. 2021
Debt Instrument [Line Items]
Interest Rate		3.38%
Notes issued at a discount		0.437%