Condensed Financial Information (Parent Company) (Condensed Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Jun. 01, 2017	Feb. 10, 2017	Dec. 31, 2016	Apr. 01, 2016	Dec. 31, 2015	Dec. 31, 2014
Investments:
Available-for-sale Securities, Debt Securities	$ 308,931			$ 289,563
Fair Value Option And Trading Securities	16,745			13,923
Short-term investments	4,870			6,523
Other Investments	17,263			19,303
Total investments	444,067			420,911
Cash and Cash Equivalents, at Carrying Value	12,701			12,651		$ 11,182	$ 9,205
Accrued Investment Income Receivable	3,524			3,308
Other Assets	8,167			7,058
Total assets	719,892			898,764
Liabilities
Payables for collateral under securities loaned and other transactions	25,723			25,873
Collateral financing arrangement	1,121			1,274
Junior subordinated debt securities	3,144			3,169
Other Liabilities	23,982			23,735
Total liabilities	661,022			831,062
Stockholders’ Equity
Preferred stock, par value $0.01 per share; $2,100 aggregate liquidation preference	0			0
Common stock, par value $0.01 per share; 3,000,000,000 shares authorized; 1,168,710,101 and 1,164,029,985 shares issued, respectively; 1,043,588,396 and 1,095,519,005 shares outstanding, respectively	12			12
Additional paid-in capital	31,111			30,944
Retained earnings	26,527			34,683		35,672	32,110
Treasury stock, at cost; 125,121,705 and 68,510,980 shares, respectively	(6,401)			(3,474)
Accumulated other comprehensive income (loss)	7,427			5,366		4,767	10,714
Total stockholders’ equity	58,676			67,531		68,098	72,208
Total liabilities and stockholders' equity	719,892			898,764
Parent Company
Investments:
Available-for-sale Securities, Debt Securities	4,510			3,894
Fair Value Option And Trading Securities	1,357			0
Short-term investments	30			148
Other Investments	127			499
Total investments	6,024			4,541
Cash and Cash Equivalents, at Carrying Value	516			334		$ 421	$ 443
Accrued Investment Income Receivable	24			74
Investment in subsidiaries	73,274			85,429
Loans to subsidiaries	100	$ 750	$ 750	1,200	$ 140
Other Assets	1,153			1,529
Total assets	81,091			93,107
Liabilities
Payables for collateral under securities loaned and other transactions	36			147
Long-term debt — unaffiliated	14,599			15,505
Long-term debt — affiliated	2,000			3,100
Collateral financing arrangement	0			2,797
Junior subordinated debt securities	2,454			1,734
Other Liabilities	3,326			2,294
Total liabilities	22,415			25,577
Stockholders’ Equity
Preferred stock, par value $0.01 per share; $2,100 aggregate liquidation preference	0			0
Common stock, par value $0.01 per share; 3,000,000,000 shares authorized; 1,168,710,101 and 1,164,029,985 shares issued, respectively; 1,043,588,396 and 1,095,519,005 shares outstanding, respectively	12			12
Additional paid-in capital	31,111			30,944
Retained earnings	26,527			34,683
Treasury stock, at cost; 125,121,705 and 68,510,980 shares, respectively	(6,401)			(3,474)
Accumulated other comprehensive income (loss)	7,427			5,366
Total stockholders’ equity	58,676			67,531
Total liabilities and stockholders' equity	$ 81,091			$ 93,108