Equity (Components of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	$ 5,347	$ 4,771
OCI before reclassifications	1,271	8,917
Deferred income tax benefit (expense)	(233)	(2,631)
AOCI before reclassifications, net of income tax	6,385	11,057
Amounts reclassified from AOCI	11	(258)
Deferred income tax benefit (expense)	0	66
Amounts reclassified from AOCI, net of income tax	11	(192)
Balance, end of period	6,396	10,865
Unrealized Investment Gains (Losses), Net of Related Offsets
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	10,766	10,315
OCI before reclassifications	733	7,670
Deferred income tax benefit (expense)	(284)	(2,549)
AOCI before reclassifications, net of income tax	11,215	15,436
Amounts reclassified from AOCI	196	17
Deferred income tax benefit (expense)	(75)	(7)
Amounts reclassified from AOCI, net of income tax	121	10
Balance, end of period	11,336	15,446
Unrealized Gains (Losses) on Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	1,865	1,458
OCI before reclassifications	210	696
Deferred income tax benefit (expense)	(73)	(199)
AOCI before reclassifications, net of income tax	2,002	1,955
Amounts reclassified from AOCI	(229)	(323)
Deferred income tax benefit (expense)	80	93
Amounts reclassified from AOCI, net of income tax	(149)	(230)
Balance, end of period	1,853	1,725
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	(5,312)	(4,950)
OCI before reclassifications	348	551
Deferred income tax benefit (expense)	122	117
AOCI before reclassifications, net of income tax	(4,842)	(4,282)
Amounts reclassified from AOCI	0	0
Deferred income tax benefit (expense)	0	0
Amounts reclassified from AOCI, net of income tax	0	0
Balance, end of period	(4,842)	(4,282)
Defined Benefit Plans Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	(1,972)	(2,052)
OCI before reclassifications	(20)	0
Deferred income tax benefit (expense)	2	0
AOCI before reclassifications, net of income tax	(1,990)	(2,052)
Amounts reclassified from AOCI	44	48
Deferred income tax benefit (expense)	(5)	(20)
Amounts reclassified from AOCI, net of income tax	39	28
Balance, end of period	$ (1,951)	$ (2,024)