Segment Information (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014 Segment	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting [Abstract]
Number of segments	6
Segment Reporting Information [Line Items]
Total assets	$ 902,337	885,296
Percent of total assets from Japan operations	10.00%
Japan
Segment Reporting Information [Line Items]
Total assets	93,800	98,400
Assets, Total [Member] | Geographic Concentration Risk [Member] | Japan
Segment Reporting Information [Line Items]
Percent of total assets from Japan operations	10.00%	11.00%
Corporate Benefit Funding
Segment Reporting Information [Line Items]
Total assets	230,124	220,612
Corporate & Other
Segment Reporting Information [Line Items]
Total assets	51,574	48,791
Divested Business [Member] | Corporate Benefit Funding
Segment Reporting Information [Line Items]
Prior Period Reclassification Adjustment		12	21
Prior Period Adjustment To Operating Earnings Tax Expense		8	13
Divested Business [Member] | Corporate & Other
Segment Reporting Information [Line Items]
Prior Period Reclassification Adjustment		14	16
Prior Period Adjustment To Operating Earnings Tax Expense		7	$ 8