AOCI Rollforward (Details 2) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		$ 394	$ 269	$ 262	$ (291)
OCI before reclassifications		125	60	254	625
Amounts reclassified from AOCI		(3)	8		3
Total other comprehensive income (loss), net of tax		122	68	254	628
Ending balance		516	337	516	337
Accumulated Other Comprehensive Income (Loss) Available For Sale Securities Impairment Other than Credit		0	1	0	1
Net unrealized gains (losses) on securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		749	590	576	20
OCI before reclassifications		98	82	268	656
Amounts reclassified from AOCI		(3)	8		4
Total other comprehensive income (loss), net of tax		95	90	268	660
Ending balance	[1]	844	680	844	680
Net unrealized gains (losses) on derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		6	7	6	8
OCI before reclassifications		0	0	0	0
Amounts reclassified from AOCI		0	0		(1)
Total other comprehensive income (loss), net of tax		0	0	0	(1)
Ending balance		6	7	6	7
Defined benefit plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(138)	(120)	(138)	(120)
OCI before reclassifications		0	0	0	0
Amounts reclassified from AOCI		0	0		0
Total other comprehensive income (loss), net of tax		0	0	0	0
Ending balance		(138)	(120)	(138)	(120)
Foreign currency translation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(222)	(207)	(181)	(198)
OCI before reclassifications		27	(22)	(14)	(31)
Amounts reclassified from AOCI		0	0		0
Total other comprehensive income (loss), net of tax		27	(22)	(14)	(31)
Ending balance		(195)	(229)	(195)	(229)
Other [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(1)	(1)	(1)	(1)
OCI before reclassifications		0	0	0	0
Amounts reclassified from AOCI		0	0		0
Total other comprehensive income (loss), net of tax		0	0	0	0
Ending balance		$ (1)	$ (1)	$ (1)	$ (1)

[1] Includes nil and $(1) million of noncredit related impairments on securities and net unrealized gains (losses) on previously impaired securities as of September 30, 2020 and September 30, 2019, respectively.