Employee Retirement Benefits (Fair Value Hierarchy Of Assets Measured At Fair Value On A Recurring Basis) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]
Available for sale securities, debt Securities	$ 9,121	$ 9,093
Available for sale securities, equity securities	4,375	3,373
Fair value of asset	14,192	13,164
Fixed Maturities [Member]
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]
Available for sale securities, debt Securities	53	60
Fixed Maturities [Member] | Corporate Fixed Maturities [Member]
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]
Available for sale securities, debt Securities	21	24
Fixed Maturities [Member] | States, Municipalities And Political Subdivisions [Member]
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]
Available for sale securities, debt Securities	32	36
Equity Securities [Member]
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]
Available for sale securities, equity securities	261	235
Equity Securities [Member] | Common Stock [Member]
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]
Available for sale securities, equity securities	208	175
Fair Value, Inputs, Level 1 [Member]
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]
Fair value of asset	4,234	3,255
Fair Value, Inputs, Level 1 [Member] | Equity Securities [Member]
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]
Available for sale securities, equity securities	208	175
Fair Value, Inputs, Level 1 [Member] | Equity Securities [Member] | Common Stock [Member]
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]
Available for sale securities, equity securities	208	175
Fair Value, Inputs, Level 2 [Member]
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]
Fair value of asset	9,954	9,904
Fair Value, Inputs, Level 2 [Member] | Fixed Maturities [Member]
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]
Available for sale securities, debt Securities	53	60
Fair Value, Inputs, Level 2 [Member] | Fixed Maturities [Member] | Corporate Fixed Maturities [Member]
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]
Available for sale securities, debt Securities	21	24
Fair Value, Inputs, Level 2 [Member] | Fixed Maturities [Member] | States, Municipalities And Political Subdivisions [Member]
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]
Available for sale securities, debt Securities	32	36
Fair Value, Inputs, Level 2 [Member] | Equity Securities [Member]
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]
Available for sale securities, equity securities	53	60
Fair Value, Inputs, Level 3 [Member]
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]
Fair value of asset	4	5
Cincinnati Financial Corporation [Member]
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]
Available for sale securities, debt Securities	75	103
Available for sale securities, equity securities	$ 1,366	$ 958