Stock-Based Associate Compensation Plans (Narrative) (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares awarded to each full-time employee for their service	10
Stock based compensation	$ 12	$ 11	$ 9
Tax benefit from compensation expense	6	5	4
Unrecognized compensation costs related to non-vested awards	20
Expected weighted-average period to recognize the unrecognized compensation costs related to non-vested awards	1 year 8 months 18 days
Options exercised, intrinsic value	17	6	1
Cash received from the exercise of options	25	10	1
Shares repurchased	577,745	311,524
Shares repurchased, value	28	12
Weighted-average remaining contractual life for exercisable awards	3 years 2 months 12 days
Shares authorized to be granted under the shareholder-approved plans	17,300,000
Shares of common stock granted in period	394,000
Performance Based Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	3.63%	4.51%
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards vesting period	3 years
Weighted-average remaining contractual life for exercisable awards	10 years
Employee Stock Option [Member] \| Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards vesting period	3 years
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards vesting period	3 years
Restricted Stock Units [Member] \| Service Based Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards other than options vested, intrinsic value	15	1	13
Awards vesting period	3 years
Restricted Stock Units [Member] \| Performance Based Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards vesting period	3 years	3 years
Number of shares issued	61,146
Expected volatility	2.87%	2.87%
Risk-free rates	0.40%	0.40%
Risk-free rates, minimum	0.00%	0.00%
Risk-free rates, maximum	200.00%	125.00%
Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock granted in period	21,363
Cincinnati Financial Corporation [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cash received from the exercise of options	25	9	4
Shares available for future issuance under the plans	7,700,000
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards exercise peirod	10 years
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options vested, intrinsic value	$ 15	$ 5	$ 2
Weighted - average expected term	10 years	10 years
Expected volatility	26.31%	26.20%
Dividend yield	3.65%	4.52%
Risk-free rates	2.00%	2.00%
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted - average expected term	9 years	8 years
Expected volatility	25.25%	25.26%
Dividend yield	3.65%	4.51%
Risk-free rates	1.82%	1.58%

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Amount of difference between fair value of the underlying shares vested during the period.

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Share Based Compensation Arrangement by Share Based Payment Award, Exercise Period

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Share Based Compensation Arrangement by Share Based Payment Award, Options, Vested in Period, Total Intrinsic Value

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The amount of expense, net of income tax, recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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Unrecognized cost of unvested share-based compensation awards.

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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

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The cash inflow associated with the amount received from holders exercising their stock options. This item inherently excludes any excess tax benefit, which the entity may have realized and reported separately.

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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The risk-free interest rate assumption that is used in valuing an option on its own shares.

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The maximum risk-free interest rate assumption that is used in valuing an option on its own shares.

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The minimum risk-free interest rate assumption that is used in valuing an option on its own shares.

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The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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Net number of share options (or share units) granted during the period.

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Weighted average remaining contractual term of exercisable stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Number of shares of stock issued as of the balance sheet date, including shares that had been issued and were previously outstanding but which are now held in the treasury.

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Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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Equity impact of the value of stock that has been repurchased during the period and has not been retired and is not held in treasury. Some state laws may mandate the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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