Insurance (Liabilities for Guarantees) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Movement In Guaranteed Benefit Liability Gross Rollforward
Balance at January 1,	$ 5,367	$ 4,425	$ 3,343
Incurred guaranteed benefits	1,383	978	1,106
Paid guaranteed benefits	(58)	(36)	(24)
Balance at December 31,	6,692	5,367	4,425
Variable Annuity Guarantees | Guaranteed Minimum Death Benefit
Movement In Guaranteed Benefit Liability Gross Rollforward
Balance at January 1,	823	611	404
Incurred guaranteed benefits	331	248	231
Paid guaranteed benefits	(58)	(36)	(24)
Balance at December 31,	1,096	823	611
Variable Annuity Guarantees | Guaranteed Minimum Income Benefit
Movement In Guaranteed Benefit Liability Gross Rollforward
Balance at January 1,	1,757	1,440	1,155
Incurred guaranteed benefits	300	317	285
Paid guaranteed benefits	0	0	0
Balance at December 31,	2,057	1,757	1,440
Universal and Variable Life Contracts | Secondary Guarantees
Movement In Guaranteed Benefit Liability Gross Rollforward
Balance at January 1,	2,787	2,374	1,784
Incurred guaranteed benefits	752	413	590
Paid guaranteed benefits	0	0	0
Balance at December 31,	3,539	2,787	2,374
Net Ceded/(Assumed)
Movement In Guaranteed Benefit Liability Gross Rollforward
Balance at January 1,	2,042	1,703	952
Incurred guaranteed benefits	632	372	750
Paid guaranteed benefits	(55)	(33)	1
Balance at December 31,	2,619	2,042	1,703
Net Ceded/(Assumed) | Secondary Guarantees
Movement In Guaranteed Benefit Liability Gross Rollforward
Balance at January 1,	2,151	1,789	1,312
Incurred guaranteed benefits	594	362	477
Paid guaranteed benefits	0	0	0
Balance at December 31,	2,745	2,151	1,789
Net Ceded/(Assumed) | Guaranteed Minimum Death Benefit
Movement In Guaranteed Benefit Liability Gross Rollforward
Balance at January 1,	(43)	(29)	(205)
Incurred guaranteed benefits	41	19	175
Paid guaranteed benefits	(54)	(33)	1
Balance at December 31,	(56)	(43)	(29)
Net Ceded/(Assumed) | Guaranteed Minimum Income Benefit
Movement In Guaranteed Benefit Liability Gross Rollforward
Balance at January 1,	(66)	(57)	(155)
Incurred guaranteed benefits	(3)	(9)	98
Paid guaranteed benefits	(1)	0	0
Balance at December 31,	(70)	(66)	(57)
Net
Movement In Guaranteed Benefit Liability Gross Rollforward
Balance at January 1,	3,325	2,722	2,391
Incurred guaranteed benefits	751	606	356
Paid guaranteed benefits	(3)	(3)	(25)
Balance at December 31,	4,073	3,325	2,722
Net | Secondary Guarantees
Movement In Guaranteed Benefit Liability Gross Rollforward
Balance at January 1,	636	585	472
Incurred guaranteed benefits	158	51	113
Paid guaranteed benefits	0	0	0
Balance at December 31,	794	636	585
Net | Guaranteed Minimum Death Benefit
Movement In Guaranteed Benefit Liability Gross Rollforward
Balance at January 1,	866	640	609
Incurred guaranteed benefits	290	229	56
Paid guaranteed benefits	(4)	(3)	(25)
Balance at December 31,	1,152	866	640
Net | Guaranteed Minimum Income Benefit
Movement In Guaranteed Benefit Liability Gross Rollforward
Balance at January 1,	1,823	1,497	1,310
Incurred guaranteed benefits	303	326	187
Paid guaranteed benefits	1	0	0
Balance at December 31,	$ 2,127	$ 1,823	$ 1,497