Other Comprehensive Income (Tables)

3 Months Ended

Mar. 31, 2019

Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]

Other comprehensive income (loss) on a pre-tax and after-tax basis

Components of other comprehensive income (loss) on a pre-tax and after-tax basis
($ in millions)	Three months ended March 31,
	2019									2018
	Pre-tax			Tax			After-tax			Pre-tax			Tax			After-tax
Unrealized net holding gains and losses arising during the period, net of related offsets	$	1,287		$	(273	)	$	1,014		$	(740	)	$	155		$	(585	)
Less: reclassification adjustment of realized capital gains and losses	51			(11		)	40			(25		)	5			(20		)
Unrealized net capital gains and losses	1,236			(262		)	974			(715		)	150			(565		)
Unrealized foreign currency translation adjustments	6			(1		)	5			(3		)	1			(2		)
Unamortized pension and other postretirement prior service credit arising during the period	—			—			—			—			—			—
Less: reclassification adjustment of prior service credit amortized into operating costs and expenses	15			(3		)	12			19			(5		)	14
Unamortized pension and other postretirement prior service credit	(15		)	3			(12		)	(19		)	5			(14		)
Other comprehensive income (loss)	$	1,227		$	(260	)	$	967		$	(737	)	$	156		$	(581	)