Reserves for Future Policy Benefits and Unpaid Losses and Loss Adjustment Expenses Level 4 P&C Liabilities for Unpaid Losses and Loss Adjustment Expenses (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Less payment
Reinsurance Recoverables					$ 23,189		$ 22,920
Reserves for Future Policy Benefits and Unpaid Losses and Loss Adjustment Expenses (Textual) [Abstract]
Current accident year benefit from discounting property and casualty reserves		$ 35	$ 34	$ 46
Accretion of discounts for prior accident years		38	31	31
Group Insurance Policies [Member]
Reserve Development
Beginning liabilities for unpaid losses and loss adjustment expenses, gross		6,084	6,308	6,547
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments					285		271		$ 267		$ 252
Beginning liabilities for unpaid losses and loss adjustment expenses, net		5,680	5,813	6,041	5,680		5,813		6,041		6,295
Add provision for unpaid losses and loss adjustment expenses
Current Year Claims and Claims Adjustment Expense		2,371	2,370	2,534
Prior years		(64)	11	17
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims		2,435	2,359	2,517
Less payment
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Current Year		1,214	1,161	1,207
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Prior Years		1,354	1,426	1,564
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid		2,568	2,587	2,771
Ending liabilities for unpaid losses and loss adjustment expenses, net		5,680	5,813	6,041
Ending liabilities for unpaid losses and loss adjustment expenses, gross		5,965	6,084	6,308
Property, Liability and Casualty Insurance Product Line [Member]
Reserve Development
Beginning liabilities for unpaid losses and loss adjustment expenses, gross		21,806	21,704	21,716
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments					2,882	[1]	3,041	[1]	3,028	[1]	3,027
Beginning liabilities for unpaid losses and loss adjustment expenses, net		18,943	18,765	18,676	18,943		18,765		18,676		$ 18,689
Add provision for unpaid losses and loss adjustment expenses
Current Year Claims and Claims Adjustment Expense		6,647	6,572	6,621
Prior years		(250)	(228)	(192)
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims		6,897	6,800	6,813
Less payment
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Current Year		2,653	2,639	2,552
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Prior Years		4,066	4,072	4,274
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid		6,719	6,711	6,826
Ending liabilities for unpaid losses and loss adjustment expenses, net		18,943	18,765	18,676
Ending liabilities for unpaid losses and loss adjustment expenses, gross		$ 21,825	$ 21,806	$ 21,704
Reinsurance Recoverables					2,515		2,730		2,735
Property, Liability and Casualty Insurance Product Line [Member]
Reserves for Future Policy Benefits and Unpaid Losses and Loss Adjustment Expenses (Textual) [Abstract]
Supplemental Information for Property, Casualty Insurance Underwriters, Discount Deducted from Reserves	[2]				$ 523		$ 556		$ 553

[1] Includes reinsurance recoverables of $2,515, $2,730 and $2,735 as of December 31, 2015, 2014 and 2013, respectively.

[2] Reserves for permanently disabled claimants have been discounted using the weighted average interest rates of 3.24%, 3.50%, and 3.50% for the years ended December 31, 2015, 2014, and 2013, respectively.