Fair Value of Assets and Liabilities (Level 3 by Pricing Source) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013		Dec. 31, 2012
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total commercial mortgage and other loans	$ 38,069	[1],[2]	$ 36,733	[1],[2]
Other Long Term Investments	9,949	[2]	10,028	[2]
Separate Account Assets	264,054		253,254
Total assets	705,615		709,298
Future policy benefits	204,190		216,050
Total liabilities	669,707		670,007
Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total commercial mortgage and other loans	303		162
Other Long Term Investments	1,392		1,383
Subtotal excluding separate account assets	339,706		358,261
Separate Account Assets	264,054	[3]	253,254	[3]
Total assets	603,760		611,515
Future policy benefits	365		3,348
Other liabilities	519		90
Notes of consolidated VIEs	2,055		1,406
Total liabilities	2,939		4,844
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Equity Securities	1,176		1,428
Total commercial mortgage and other loans	21		48
Other Long Term Investments	1,082		1,053
Other assets	20		33
Subtotal excluding separate account assets	8,528	[4]	8,605	[4]
Separate Account Assets	21,672	[3]	21,132	[3]
Total assets	30,200		29,737
Future policy benefits	365		3,348
Other liabilities	6		0
Notes of consolidated VIEs	2,055		1,406
Total liabilities	2,426		4,754
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Internal Pricing [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Equity Securities	114	[5]	101	[5]
Total commercial mortgage and other loans	21	[5]	48	[5]
Other Long Term Investments	10	[5]	9	[5]
Other assets	20	[5]	33	[5]
Subtotal excluding separate account assets	1,206	[4],[5]	1,489	[4],[5]
Separate Account Assets	20,771	[5]	20,422	[5]
Total assets	21,977	[5]	21,911	[5]
Future policy benefits	365	[5]	3,348	[5]
Other liabilities	6	[5]
Notes of consolidated VIEs	0	[5]	0	[5]
Total liabilities	371	[5]	3,348	[5]
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Internal Pricing [Member] | Separate Accounts Asset [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total commercial mortgage and other loans	791		833
Real Estate Investments	19,892		19,518
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | External Priced [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Equity Securities	1,062	[6]	1,327	[6]
Total commercial mortgage and other loans	0	[6]	0	[6]
Other Long Term Investments	1,072	[6]	1,044	[6]
Other assets	0	[6]	0	[6]
Subtotal excluding separate account assets	7,322	[4],[6]	7,116	[4],[6]
Separate Account Assets	901	[6]	710	[6]
Total assets	8,223	[6]	7,826	[6]
Future policy benefits	0	[6]	0	[6]
Other liabilities	0	[6]
Notes of consolidated VIEs	2,055	[6]	1,406	[6]
Total liabilities	2,055	[6]	1,406	[6]
Fair Value, Inputs, Level 3 [Member] | Foreign Government Debt [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	13
Fair Value, Inputs, Level 3 [Member] | Foreign Government Debt [Member] | Fair Value, Measurements, Recurring [Member] | Internal Pricing [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	0	[5]
Fair Value, Inputs, Level 3 [Member] | Foreign Government Debt [Member] | Fair Value, Measurements, Recurring [Member] | External Priced [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	13	[6]
Fair Value, Inputs, Level 3 [Member] | Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	1,473		1,764
Fair Value, Inputs, Level 3 [Member] | Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Internal Pricing [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	711	[5]	889	[5]
Fair Value, Inputs, Level 3 [Member] | Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | External Priced [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	762	[6]	875	[6]
Fair Value, Inputs, Level 3 [Member] | Asset-backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	4,433		4,134
Fair Value, Inputs, Level 3 [Member] | Asset-backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Internal Pricing [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	287	[5]	338	[5]
Fair Value, Inputs, Level 3 [Member] | Asset-backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | External Priced [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	4,146	[6]	3,796	[6]
Fair Value, Inputs, Level 3 [Member] | Commercial Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	297		132
Fair Value, Inputs, Level 3 [Member] | Commercial Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Internal Pricing [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	39	[5]	68	[5]
Fair Value, Inputs, Level 3 [Member] | Commercial Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | External Priced [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	258	[6]	64	[6]
Fair Value, Inputs, Level 3 [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	13		13
Fair Value, Inputs, Level 3 [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Internal Pricing [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	4	[5]	3	[5]
Fair Value, Inputs, Level 3 [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | External Priced [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	$ 9	[6]	$ 10	[6]

[1] Includes loans held at fair value.

[2]          (1) See Note 5 for details of balances associated with variable interest entities.

[3] Separate account assets represent segregated funds that are invested for certain customers. Investment risks associated with market value changes are borne by the customers, except to the extent of minimum guarantees made by the Company with respect to certain accounts. Separate account assets classified as Level 3 consist primarily of real estate and real estate investment funds. Separate account liabilities are not included in the above table as they are reported at contract value and not fair value in the Company’s Unaudited Interim Consolidated Statement of Financial Position.

[4] Includes assets classified as fixed maturities available-for-sale, trading account assets supporting insurance liabilities and other trading account assets.

[5] Represents valuations which could incorporate internally-derived and market inputs. See below for additional information related to internally-developed valuation for significant items in the above table.

[6] Represents unadjusted prices from independent pricing services and independent non-binding broker quotes where pricing inputs are not readily available.