Fair Value Measurements (Details 4) - USD ($) $ in Millions		Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2014
Financial assets:
Cash and cash equivalents		$ 1,548	$ 1,220	$ 1,216	$ 1,343
Mortgage loans		1,159	1,067
Policy loans		195	201
Financial liabilities:
Long-term debt		998	998
Level 1 [Member]
Financial assets:
Cash and cash equivalents		1,548	1,220
Mortgage loans		0	0
Policy loans		0	0
Total financial assets not accounted for at fair value		1,548	1,220
Financial liabilities:
Annuity benefits accumulated	[1]	0	0
Long-term debt		0	0
Total financial liabilities not accounted for at fair value		0	0
Level 2 [Member]
Financial assets:
Cash and cash equivalents		0	0
Mortgage loans		0	0
Policy loans		0	0
Total financial assets not accounted for at fair value		0	0
Financial liabilities:
Annuity benefits accumulated	[1]	0	0
Long-term debt		1,126	1,105
Total financial liabilities not accounted for at fair value		1,126	1,105
Level 3 [Member]
Financial assets:
Cash and cash equivalents		0	0
Mortgage loans		1,173	1,074
Policy loans		195	201
Total financial assets not accounted for at fair value		1,368	1,275
Financial liabilities:
Annuity benefits accumulated	[1]	28,459	25,488
Long-term debt		15	15
Total financial liabilities not accounted for at fair value		28,474	25,503
Carrying Value [Member]
Financial assets:
Cash and cash equivalents		1,548	1,220
Mortgage loans		1,159	1,067
Policy loans		195	201
Total financial assets not accounted for at fair value		2,902	2,488
Financial liabilities:
Annuity benefits accumulated	[1]	28,396	26,422
Long-term debt		1,007	1,000
Total financial liabilities not accounted for at fair value		29,403	27,422
Fair Value [Member]
Financial assets:
Cash and cash equivalents		1,548	1,220
Mortgage loans		1,173	1,074
Policy loans		195	201
Total financial assets not accounted for at fair value		2,916	2,495
Financial liabilities:
Annuity benefits accumulated	[1]	28,459	25,488
Long-term debt		1,141	1,120
Total financial liabilities not accounted for at fair value		$ 29,600	$ 26,608

[1] Excludes $200 million of life contingent annuities in the payout phase at both June 30, 2016 and December 31, 2015.