Segment Information (Premiums, Universal Life and Investment-Type Policy Fees and Other Revenues by Major Product Groups) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Total premiums, universal life and investment-type product policy fees and other revenues	$ 25,658	$ 24,537	$ 23,849
Life insurance
Segment Reporting Information [Line Items]
Total premiums, universal life and investment-type product policy fees and other revenues	13,865	13,482	13,424
Accident and health insurance
Segment Reporting Information [Line Items]
Total premiums, universal life and investment-type product policy fees and other revenues	7,247	6,873	6,458
Annuities
Segment Reporting Information [Line Items]
Total premiums, universal life and investment-type product policy fees and other revenues	4,352	4,007	3,800
Non-insurance
Segment Reporting Information [Line Items]
Total premiums, universal life and investment-type product policy fees and other revenues	$ 194	$ 175	$ 167