Derivative Financial Instruments (Details 4) $ in Millions	Sep. 30, 2016 USD ($) party	Dec. 31, 2015 USD ($) party
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Cash and securities pledged as collateral by counterparties	$ 5
Securities pledged as collateral to counterparties	$ 6
Credit Derivatives
Number of counter-parties (in Party) | party	5	9
Notional amount	$ 107	$ 312
Credit exposure	4	14
Exposure, net of collateral	1	6
Gross liability fair value of contracts containing credit-risk-contingent features	4	9
Gross asset fair value of contracts containing credit-risk-contingent features and subject to MNAs	(1)	(1)
Collateral posted under MNAs for contracts containing credit-risk-contingent features	0	(7)
Maximum amount of additional exposure for contracts with credit-risk-contingent features if all features were triggered concurrently	$ 3	$ 1
A+
Credit Derivatives
Number of counter-parties (in Party) | party	1	1
Notional amount	$ 63	$ 82
Credit exposure	3	5
Exposure, net of collateral	$ 0	$ 0
A
Credit Derivatives
Number of counter-parties (in Party) | party	3	5
Notional amount	$ 43	$ 178
Credit exposure	1	6
Exposure, net of collateral	$ 1	$ 6
A-
Credit Derivatives
Number of counter-parties (in Party) | party	0	1
Notional amount	$ 0	$ 16
Credit exposure	0	3
Exposure, net of collateral	$ 0	$ 0
BBB+
Credit Derivatives
Number of counter-parties (in Party) | party	1	2
Notional amount	$ 1	$ 36
Credit exposure	0	0
Exposure, net of collateral	$ 0	$ 0