Condensed Financial Statements Of Parent Company Condensed Balance Sheets (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Financial Statements, Captions
Fixed maturities, amortized cost	$ 10,643	$ 10,314
Investments
Fixed maturities, at fair value (amortized cost: 2018—$35; 2017—$35)	10,689	10,699
Equity securities, at fair value (cost: 2018—$1,282; 2017—$1,159)	5,920	6,249
Other invested assets	123	103
Total investments	16,732	17,051
Cash and cash equivalents	784	657	$ 777	$ 544
Investment income receivable	132	134
Land, building and equipment, net, for company use (accumulated depreciation: 2018—$121; 2017—$115)	195	185
Other assets	308	216
Total assets	21,935	21,843
Liabilities
Deferred federal income tax	825	995
Long-term debt	788	787
Other liabilities	804	792
Total liabilities	14,102	13,600
Shareholders' Equity
Common stock	397	397
Paid-in capital	1,281	1,265
Retained earnings	7,625	5,180
Accumulated other comprehensive income	22	2,788
Treasury stock at cost	(1,492)	(1,387)
Total shareholders' equity	7,833	8,243	7,060
Total liabilities and shareholders' equity	21,935	21,843
Equity securities, cost	3,368	3,094
Cincinnati Financial Corporation
Condensed Financial Statements, Captions
Fixed maturities, amortized cost	35	35
Investments
Fixed maturities, at fair value (amortized cost: 2018—$35; 2017—$35)	35	37
Equity securities, at fair value (cost: 2018—$1,282; 2017—$1,159)	2,234	2,275
Other invested assets	36	35
Total investments	2,305	2,347
Cash and cash equivalents	209	199	$ 248	$ 106
Equity in net assets of subsidiaries	6,152	6,542
Investment income receivable	6	8
Land, building and equipment, net, for company use (accumulated depreciation: 2018—$121; 2017—$115)	137	130
Income tax receivable	1	15
Other assets	48	52
Due from subsidiaries	106	107
Total assets	8,964	9,400
Liabilities
Dividends declared but unpaid	86	82
Deferred federal income tax	198	234
Long-term debt	788	787
Other liabilities	59	54
Total liabilities	1,131	1,157
Shareholders' Equity
Common stock	397	397
Paid-in capital	1,281	1,265
Retained earnings	7,625	5,180
Accumulated other comprehensive income	22	2,788
Treasury stock at cost	(1,492)	(1,387)
Total shareholders' equity	7,833	8,243
Total liabilities and shareholders' equity	8,964	9,400
Equity securities, cost	$ 1,282	$ 1,159