Equity (Components of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	$ 6,396	$ 10,865	$ 5,347	$ 4,771
OCI before reclassifications	3,453	5,288	4,724	14,205
Deferred income tax benefit (expense)	(1,132)	(1,608)	(1,365)	(4,239)
AOCI before reclassifications, net of income tax	8,717	14,545	8,706	14,737
Amounts reclassified from AOCI	(435)	111	(424)	(147)
Deferred income tax benefit (expense)	154	(24)	154	42
Amounts reclassified from AOCI, net of income tax	(281)	87	(270)	(105)
Balance, end of period	8,436	14,632	8,436	14,632
Unrealized Investment Gains (Losses), Net of Related Offsets
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	11,336	15,446	10,766	10,315
OCI before reclassifications	3,290	4,268	4,023	11,938
Deferred income tax benefit (expense)	(1,132)	(1,388)	(1,416)	(3,937)
AOCI before reclassifications, net of income tax	13,494	18,326	13,373	18,316
Amounts reclassified from AOCI	(47)	(183)	149	(166)
Deferred income tax benefit (expense)	22	61	(53)	54
Amounts reclassified from AOCI, net of income tax	(25)	(122)	96	(112)
Balance, end of period	13,469	18,204	13,469	18,204
Unrealized Gains (Losses) on Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	1,853	1,725	1,865	1,458
OCI before reclassifications	(7)	800	203	1,496
Deferred income tax benefit (expense)	3	(269)	(70)	(468)
AOCI before reclassifications, net of income tax	1,849	2,256	1,998	2,486
Amounts reclassified from AOCI	(429)	243	(658)	(80)
Deferred income tax benefit (expense)	149	(68)	229	25
Amounts reclassified from AOCI, net of income tax	(280)	175	(429)	(55)
Balance, end of period	1,569	2,431	1,569	2,431
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	(4,842)	(4,282)	(5,312)	(4,950)
OCI before reclassifications	169	209	517	760
Deferred income tax benefit (expense)	(6)	53	116	170
AOCI before reclassifications, net of income tax	(4,679)	(4,020)	(4,679)	(4,020)
Amounts reclassified from AOCI	0	0	0	0
Deferred income tax benefit (expense)	0	0	0	0
Amounts reclassified from AOCI, net of income tax	0	0	0	0
Balance, end of period	(4,679)	(4,020)	(4,679)	(4,020)
Defined Benefit Plans Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	(1,951)	(2,024)	(1,972)	(2,052)
OCI before reclassifications	1	11	(19)	11
Deferred income tax benefit (expense)	3	(4)	5	(4)
AOCI before reclassifications, net of income tax	(1,947)	(2,017)	(1,986)	(2,045)
Amounts reclassified from AOCI	41	51	85	99
Deferred income tax benefit (expense)	(17)	(17)	(22)	(37)
Amounts reclassified from AOCI, net of income tax	24	34	63	62
Balance, end of period	$ (1,923)	$ (1,983)	$ (1,923)	$ (1,983)