Consolidating Financial Statements (details) - Consolidating Statement of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Consolidating Statement of Comprehensive Income
Net income	$ 595	$ 664	$ 1,212	$ 1,355
Changes in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income	327	879	471	1,593
Changes in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income	2	12	2	17
Net changes in benefit plan assets and obligations	17	18	34	34
Net changes in unrealized foreign currency translation	48	(35)	89	68
Other comprehensive income before income taxes	394	874	596	1,712
Income tax expense (benefit)	123	323	185	590
Other comprehensive income (loss), net of taxes, before other comprehensive income of subsidiaries	271	551	411	1,122
Other comprehensive income, net of taxes	271	551	411	1,122
Comprehensive income	866	1,215	1,623	2,477
Reportable Legal Entities [Member] | TPC [Member]
Consolidating Statement of Comprehensive Income
Net income	438	502	946	1,027
Changes in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income	296	570	389	1,055
Changes in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income	1	6	2	8
Net changes in benefit plan assets and obligations		18		18
Net changes in unrealized foreign currency translation	14	25	39	119
Other comprehensive income before income taxes	311	619	430	1,200
Income tax expense (benefit)	102	216	139	397
Other comprehensive income (loss), net of taxes, before other comprehensive income of subsidiaries	209	403	291	803
Other comprehensive income, net of taxes	209	403	291	803
Comprehensive income	647	905	1,237	1,830
Reportable Legal Entities [Member] | Other Subsidiaries [Member]
Consolidating Statement of Comprehensive Income
Net income	162	203	306	408
Changes in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income	85	306	129	534
Changes in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income	1	6		9
Net changes in benefit plan assets and obligations	(1)	19	(1)	20
Net changes in unrealized foreign currency translation	34	(60)	50	(51)
Other comprehensive income before income taxes	119	271	178	512
Income tax expense (benefit)	33	113	49	192
Other comprehensive income (loss), net of taxes, before other comprehensive income of subsidiaries	86	158	129	320
Other comprehensive income, net of taxes	86	158	129	320
Comprehensive income	248	361	435	728
Reportable Legal Entities [Member] | TRV [Member]
Consolidating Statement of Comprehensive Income
Net income	595	664	1,212	1,355
Changes in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income	(54)	3	(47)	4
Net changes in benefit plan assets and obligations	18	(19)	35	(4)
Other comprehensive income before income taxes	(36)	(16)	(12)
Income tax expense (benefit)	(12)	(6)	(3)	1
Other comprehensive income (loss), net of taxes, before other comprehensive income of subsidiaries	(24)	(10)	(9)	(1)
Other comprehensive income of subsidiaries	295	561	420	1,123
Other comprehensive income, net of taxes	271	551	411	1,122
Comprehensive income	866	1,215	1,623	2,477
Eliminations [Member]
Consolidating Statement of Comprehensive Income
Net income	(600)	(705)	(1,252)	(1,435)
Other comprehensive income of subsidiaries	(295)	(561)	(420)	(1,123)
Other comprehensive income, net of taxes	(295)	(561)	(420)	(1,123)
Comprehensive income	$ (895)	$ (1,266)	$ (1,672)	$ (2,558)