AOCI Rollforward (Details 2) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		$ (291)	$ 229
Cumulative effect of change in accounting policies			(1)
OCI before reclassifications		331	(229)
Amounts reclassified from AOCI		(5)	(4)
Total other comprehensive income (loss), net of tax		326	(233)
Ending balance		35	(5)
Net unrealized gains (losses) on securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		20	486
OCI before reclassifications		326	(258)
Amounts reclassified from AOCI		(4)	(4)
Total other comprehensive income (loss), net of tax		322	(262)
Ending balance	[1]	342	223
Net unrealized gains (losses) on derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		8	8
OCI before reclassifications		0	0
Amounts reclassified from AOCI		(1)	0
Total other comprehensive income (loss), net of tax		(1)	0
Ending balance		7	8
Defined benefit plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(120)	(97)
OCI before reclassifications		0	0
Amounts reclassified from AOCI		0	0
Total other comprehensive income (loss), net of tax		0	0
Ending balance		(120)	(97)
Foreign currency translation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(198)	(167)
OCI before reclassifications		5	29
Amounts reclassified from AOCI		0	0
Total other comprehensive income (loss), net of tax		5	29
Ending balance		(193)	(138)
Other [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(1)	(1)
OCI before reclassifications		0	0
Amounts reclassified from AOCI		0	0
Total other comprehensive income (loss), net of tax		0	0
Ending balance	[1]	$ (1)	(1)
Cumulative effect of adoption of equity securities guidance
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative effect of change in accounting policies				$ 0
Cumulative effect of adoption of equity securities guidance | Net unrealized gains (losses) on securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative effect of change in accounting policies			$ (1)

[1] Includes $(4) million and nil of noncredit related impairments on securities and net unrealized gains (losses) on previously impaired securities as of March 31, 2019 and March 31, 2018, respectively.