Schedule II (Details) - Condensed Balance Sheet - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Condensed Balance Sheet
Fixed maturities, at fair value	$ 63,464	$ 62,694
Equity securities, at fair value	368
Equity securities, available for sale, at fair value		453
Short-term securities	3,985	4,895
Total assets	104,233	103,483
Debt	6,564	6,571
Total liabilities	81,339	79,752
Common stock (1,750.0 shares authorized; 263.7 and 271.5 shares issued, 263.6 and 271.4 shares outstanding)	23,144	22,886
Retained earnings	35,204	33,462
Accumulated other comprehensive loss	(1,859)	(343)
Treasury stock, at cost (510.9 and 500.9 shares)	(33,595)	(32,274)
Total shareholders’ equity	22,894	23,731	$ 23,221
Total liabilities and shareholders’ equity	$ 104,233	$ 103,483
Common stock, shares authorized (in shares)	1,750,000,000	1,750,000,000
Common stock, shares issued (in shares)	263,700,000	271,500,000
Common stock, shares outstanding (in shares)	263,600,000	271,400,000
Treasury stock, at cost, shares (in shares)	510,900,000	500,900,000
Travelers [Member]
Condensed Balance Sheet
Fixed maturities, at fair value	$ 84	$ 82
Equity securities, at fair value	171
Equity securities, available for sale, at fair value		181
Short-term securities	1,371	1,230
Investment in subsidiaries	26,993	27,946
Other assets	649	692
Total assets	29,268	30,131
Debt	5,871	5,878
Other liabilities	496	524
Total liabilities	6,367	6,402
Common stock (1,750.0 shares authorized; 263.7 and 271.5 shares issued, 263.6 and 271.4 shares outstanding)	23,144	22,886
Retained earnings	35,211	33,460
Accumulated other comprehensive loss	(1,859)	(343)
Treasury stock, at cost (510.9 and 500.9 shares)	(33,595)	(32,274)
Total shareholders’ equity	22,901	23,729
Total liabilities and shareholders’ equity	$ 29,268	$ 30,131
Common stock, shares authorized (in shares)	1,750,000,000	1,750,000,000
Common stock, shares issued (in shares)	263,700,000	271,500,000
Common stock, shares outstanding (in shares)	263,600,000	271,400,000
Treasury stock, at cost, shares (in shares)	510,900,000	500,900,000