Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 1,139	$ 1,054	$ 2,690	$ 2,366
Other comprehensive income (loss), net of tax:
Change in net unrealized gains/losses on investments	238	(72)	595	(317)
Change in non-credit component of other-than-temporary impairment losses on investments	(1)	0	(1)	0
Change in net unrealized losses on cash flow hedges	0	3	3	32
Change in net periodic pension and postretirement costs	3	8	6	15
Foreign currency translation adjustments	0	(1)	0	0
Other comprehensive income (loss)	240	(62)	603	(270)
Total comprehensive income	$ 1,379	$ 992	$ 3,293	$ 2,096